Mitosis-targeted anti-cancer therapies: where they stand

Functionalized Niosomes for Co-Delivery of Curcumin and Imatinib Mesylate to Treat Breast Cancer: In Vitro and In Vivo Investigations

Breast cancer is notable for its aggressive mutations, high resistance, and delayed diagnosis. Traditional treatments often cause severe side effects, highlighting the need for targeted therapies. This study developed a targeted delivery system using folic acid and Arginylglycylaspartic acid (RGD)-modified niosomes to deliver hydrophilic imatinib mesylate (IM) and hydrophobic curcumin (C) to treat breast cancer. The formulations were prepared and characaterized for size, zet potential, polydispersity index, % entrapment efficiency, and morphology. Moreover, FTIR (Fourier Transform Infrared) study negated incompatibility. In vitro drug release study was carried out at two different pH. In vitro cytotoxicity (dose dependent and ROS activity) and in vivo bioavailability studies were conducted to generate a proof of concept. The dual drug-loaded niosomal vesicles (R-F-PL64oxNS@IM-C) were designed for effective delivery of IM and C having particle size (< 300 nm) with high zeta potential (- 18 mV). The formulation achieved high entrapment efficiency (>70%) for both drugs with sustained release over 36 h at the explored two pH. In vitro results using MCF- 7 cells revealed significant cell death by R-F-PL64oxNS@IM-C as compared to pure drugs (IM & C) through upregulation and downregulation of proapoptotic and antiapoptotic genes, respectively. In vivo studies showed approximately 1.9- and 5-fold higher biodistribution of C and IM, respectively using targeted niosomal systems as compared to pure drugs. The pharmacokinetic analysis revealed that Cmax and AUC of IM from R-F-PL64oxNS@IM and C from R-F-PL64oxNS@IM-C were significantly higher compared to pure IM and curcumin. Moreover, the Tmax had also increased for both IM (3 h) and C (3 h) using RGD and folic acid guided niosomal formulation suggesting its enhanced retention in systemic circulation leading to more bioavailability as compared to IM (0.5 h) and C (0.5 h). The targeted delivery also led to significant reduction in TNF-α levels, indicating improved therapeutic potential. The developed R-F-PL64oxNS@IM-C shown more precisely killing of breast cancer cell than pure IM and C.

GMCL1 Controls 53BP1 Stability and Modulates Paclitaxel Sensitivity in Cancer

The Mitotic Surveillance Pathway (MSP) monitors the duration of M-phase. Prolonged mitosis, caused by spindle attachment defects or microtubule-targeting drugs such as the taxane paclitaxel, induces the formation of the ternary "mitotic stopwatch" complex consisting of 53BP1, USP28, and p53. This event protects p53 from degradation, resulting in cell cycle arrest or apoptosis in daughter cells. In paclitaxel-resistant cancers, cells bypass the MSP, enabling unchecked proliferation and survival, although the underlying mechanisms remain unknown. Here, we demonstrate that 53BP1 physically interacts with GMCL1 but not its paralog, GMCL2, and we mapped the interaction regions on both proteins. CRL3GMCL1 functions as a ubiquitin ligase that targets 53BP1 for degradation during M phase, impacting p53 levels in daughter cells. High GMCL1 expression significantly correlates with resistance to paclitaxel in cancer cell lines with wild-type p53, including endometrial, breast, and upper aerodigestive tract cancer cells. Loss of GMCL1 restores paclitaxel sensitivity in p53 expressing cells but not in p53 deficient cells. We propose that in cancers with high GMCL1 levels, the CRL3GMCL1-mediated degradation of 53BP1 prevents the formation of the mitotic stopwatch complex, leading to p53 degradation and sustained proliferation. Finally, our results indicate that GMCL1 inhibition represents a novel strategy to restore taxane sensitivity in resistant cancers.

Osmotic stress influences microtubule drug response via WNK1 kinase signaling

Ion homeostasis is critical for numerous cellular processes, and disturbances in ionic balance underlie diverse pathological conditions, including cancer progression. Targeting ion homeostasis is even considered as a strategy to treat cancer. However, very little is known about how ion homeostasis may influence anticancer drug response. In a genome-wide CRISPR-Cas9 resistance drug screen, we identified and validated the master osmostress regulator WNK1 kinase as a modulator of the response to the mitotic inhibitor rigosertib. Osmotic stress and WNK1 inactivation lead to an altered response not only to rigosertib treatment but also to other microtubule-related drugs, minimizing the prototypical mitotic arrest produced by these compounds. This effect is due to an alteration in microtubule stability and polymerization dynamics, likely maintained by fluctuations in intracellular molecular crowding upon WNK1 inactivation. This promotes resistance to microtubule depolymerizing compounds, and increased sensitivity to microtubule stabilizing drugs. In summary, our data proposes WNK1 osmoregulation activity as an important modulator for microtubule-associated chemotherapy response.

Toxoplasma replication is inhibited by MMV676477 without development of resistance

Protozoan parasites cause life-threatening infections in both humans and animals, including agriculturally significant livestock. Available treatments are typically narrow spectrum and are complicated by drug toxicity and the development of resistant parasites. Protozoan tubulin is an attractive target for the development of broad-spectrum antimitotic agents. The Medicines for Malaria Pathogen Box compound MMV676477 was previously shown to inhibit replication of kinetoplastid parasites, such as Leishmania amazonensis and Trypanosoma brucei, and the apicomplexan parasite Plasmodium falciparum by selectively stabilizing protozoan microtubules. In this report, we show that MMV676477 inhibits intracellular growth of the human apicomplexan pathogen Toxoplasma gondii with an EC50 value of ~50 nM. MMV676477 does not stabilize vertebrate microtubules or cause other toxic effects in human fibroblasts. The availability of tools for genetic studies makes Toxoplasma a useful model for studies of the cytoskeleton. We conducted a forward genetics screen for MMV676477 resistance, anticipating that missense mutations would delineate the binding site on protozoan tubulin. Unfortunately, we were unable to use genetics to dissect target interactions because no resistant parasites emerged. This outcome suggests that future drugs based on the MMV676477 scaffold would be less likely to be undermined by the emergence of drug resistance.

DeSUMOylating isopeptidase 1 participates in the faithful chromosome segregation and vincristine sensitivity

SUMOylation, the modification of proteins with a small ubiquitin-like modifier (SUMO), is known to regulate various cellular events, including cell division. This process is dynamic, with its status depending on the balance between SUMOylation and deSUMOylation. While the regulation of cell division by sentrin-specific protease (SENP) family proteins through deSUMOylation has been investigated, the role of another deSUMOylase, deSUMOylating isopeptidase 1 (DESI1), remains unknown. In this study, we explored DESI1's role in cell division. Knockdown of DESI1 accelerated cell division progression, leading to a significant increase in abnormal chromosome segregation. These phenotypes were rescued by re-expression of wild-type DESI1, but not catalytically inactive DESI1. DESI1 knockdown reduced the mitotic arrest caused by nocodazole, suggesting DESI1's involvement in the spindle assembly checkpoint (SAC). Localization of Aurora B, a key SAC regulator, at the metaphase chromosomes was reduced due to decreased Aurora B expression upon DESI1 knockdown. Consistently, DESI1 knockdown reduced transcription of FoxM1 target genes, such as Aurora B, cyclin B1, and CENP-F. The TCGA database showed that both decreased and increased DESI1 expression levels are associated with poor prognosis in patients with certain cancer types. Importantly, we found that DESI1 knockdown reduced sensitivity to vincristine by inducing mitotic slippage. These results suggest that DESI1 is required for faithful chromosome segregation via regulating FoxM1 transcriptional activity and thereby SAC activity in an isopeptidase activity-dependent manner. Our findings identified DESI1 as a novel regulator of cell division and a factor affecting cancer chemotherapy.

Deciphering the Role of ASPM in Breast Cancer: A Comprehensive Multicohort Study

BACKGROUND

Assembly factor for spindle microtubules (ASPM) has gained significant attention in cancer research due to its association with tumor growth and progression. Through the analysis of large-scale genomic datasets, ASPM has been identified as the top upregulated gene in breast cancer (BC), characterized by high proliferation. This multicohort study aimed to investigate the clinicopathological and prognostic significance of ASPM mRNA and protein expression in BC.

METHODS

ASPM mRNA expression was assessed using the Cancer Genome Atlas (TCGA) BC cohort and has been further validated in the Molecular Taxonomy of BC International Consortium (METABRIC) (n = 1980), The Uppsala cohort (n = 249), in addition to the combined multicentric cohort (n = 7252). ASPM protein expression was evaluated in a large BC cohort (n = 1300) using immunohistochemistry. The correlations between ASPM expression, clinicopathological parameters, molecular subtypes and outcome were assessed. The response to taxane treatment was compared to the clinical prognosis of ASPM using the ROC plotter.

RESULTS

High ASPM mRNA and protein expression were significantly associated with aggressive BC features and poor survival across all cohorts. The association with poor outcomes was maintained in the adjuvant chemotherapy and radio-therapy-treated patients. Responders to taxane treatment showed significantly elevated ASPM levels compared to non-responders.

CONCLUSIONS

High ASPM expression predicts poor prognosis in BC. It may play a role in treatment resistance within a specific subgroup of patients. Further clinical trials are warranted to explore the potential of ASPM as a target for therapeutic interventions in cancer.

Inhibition of p38-MK2 pathway enhances the efficacy of microtubule inhibitors in breast cancer cells

Microtubule-targeting agents (MTAs) have been successfully translated from basic research into clinical therapies and have been widely used as first- and second-line chemotherapy drugs for various cancers. However, current MTAs exhibit positive responses only in subsets of patients and are often accompanied by side effects due to their impact on normal cells. This underscores an urgent need to develop novel therapeutic strategies that enhance MTA efficacy while minimizing toxicity to normal tissues. In this study, we demonstrate that inhibition of the p38-MK2 (MAP kinase-activated protein kinase 2) pathway sensitizes cancer cells to MTA treatment. We utilize CMPD1, a dual-target inhibitor, to concurrently suppress the p38-MK2 pathway and microtubule dynamicity. In addition to established role as an MK2 inhibitor, we find that CMPD1 rapidly induces microtubule depolymerization, preferentially at the microtubule plus-end, leading to the inhibition of tumor growth and cancer cell invasion in both in vitro and in vivo models. Notably, 10 nM CMPD1 is sufficient to induce irreversible mitotic defects in cancer cells, but not in non-transformed RPE1 cells, highlighting its high specificity to cancer cells. We further validate that a specific p38-MK2 inhibitor significantly potentiates the efficacy of sub-clinical concentrations of MTA. In summary, our findings suggest that the p38-MK2 pathway presents a promising therapeutic target in combination with MTAs in cancer treatment.

Harnessing bacterial metabolites for enhanced cancer chemotherapy: unveiling unique therapeutic potentials

Cancer poses a serious threat to health globally, with millions diagnosed every year. According to Global Cancer Statistics 2024, about 20 million new cases were reported in 2022, and 9.7 million people worldwide died of this condition. Advanced therapies include combination of one or more treatment procedures, depending on the type, stage, and particular genetic constitution of the cancer, which may include surgery, radiotherapy, chemotherapy, immunotherapy, hormone therapy, targeted therapy, and stem cell transplant. Also, awareness about lifestyle changes, preventive measures and screening at early stages has reduced the incidence of the disease; still, there is a major failure in controlling the incidence of cancer because of its complex and multifaceted nature. With increasing interest in bacterial metabolites as possible novel and effective treatment options in cancer therapy, their main benefits include not only direct anticancer effects but also the modulation of the immune system and potential for targeted and combination therapies. They can therefore be used in combination with chemotherapy, radiotherapy, or immunotherapy to improve outcomes or reduce side effects. Furthermore, nanoparticle-based delivery systems have the potential to enhance the potency and safety of anticancer drugs by providing improved stability, targeted release, and controlled delivery.

HURP binding to the vinca domain of β-tubulin accounts for cancer drug resistance

Vinca alkaloids, a class of tubulin-binding agent, are widely used in treating cancer, yet the emerging resistance compromises their efficacy. Hepatoma up-regulated protein (HURP), a microtubule-associated protein displaying heightened expression across various cancer types, reduces cancer cells' sensitivity to vinca-alkaloid drugs upon overexpression. However, the molecular basis behind this drug resistance remains unknown. Here we discover a tubulin-binding domain within HURP, and establish its role in regulating microtubule growth. Cryo-EM analysis reveals interactions between HURP's tubulin-binding domain and the vinca domain on β-tubulin -- the site targeted by vinca alkaloid drugs. Importantly, HURP competes directly with vinorelbine, a vinca alkaloid-based chemotherapeutic agent, countering microtubule growth defects caused by vinorelbine both in vitro and in vivo. Our findings elucidate a mechanism driving drug resistance in HURP-overexpressing cancer cells and emphasize HURP tubulin-binding domain's role in mitotic spindle assembly. This underscores its potential as a therapeutic target to improve cancer treatment.

Dual TTK/PLK1 inhibition has potent anticancer activity in TNBC as monotherapy and in combination

Background

Threonine tyrosine kinase (TTK) and polo-like kinase 1 (PLK1) are common essential kinases that collaborate in activating the spindle assembly checkpoint (SAC) at the kinetochore, ensuring appropriate chromosome alignment and segregation prior to mitotic exit. Targeting of either TTK or PLK1 has been clinically evaluated in cancer patients; however, dual inhibitors have not yet been pursued. Here we present the in vitro and in vivo characterization of a first in class, dual TTK/PLK1 inhibitor (BAL0891).

Methods

Mechanism of action studies utilized biochemical kinase and proteomics-based target-engagement assays. Cellular end-point assays included immunoblot- and flow cytometry-based cell cycle analyses and SAC integrity evaluation using immunoprecipitation and immunofluorescence approaches. Anticancer activity was assessed in vitro using cell growth assays and efficacy was evaluated, alone and in combination with paclitaxel and carboplatin, using mouse models of triple negative breast cancer (TNBC).

Results

BAL0891 elicits a prolonged effect on TTK, with a transient activity on PLK1. This unique profile potentiates SAC disruption, forcing tumor cells to aberrantly exit mitosis with faster kinetics than observed with a TTK-specific inhibitor. Broad anti-proliferative activity was demonstrated across solid tumor cell lines in vitro. Moreover, intermittent intravenous single-agent BAL0891 treatment of the MDA-MB-231 mouse model of TNBC induced profound tumor regressions associated with prolonged TTK and transient PLK1 in-tumor target occupancy. Furthermore, differential tumor responses across a panel of thirteen TNBC patient-derived xenograft models indicated profound anticancer activity in a subset (~40%). Using a flexible dosing approach, pathologically confirmed cures were observed in combination with paclitaxel, whereas synergy with carboplatin was schedule dependent.

Conclusions

Dual TTK/PLK1 inhibition represents a novel approach for the treatment of human cancer, including TNBC patients, with a potential for potent anticancer activity and a favorable therapeutic index. Moreover, combination approaches may provide an avenue to expand responsive patient populations.

DNA repair is efficient in irradiated M phase zygotes

In somatic cells, DNA repair is attenuated during mitosis to prevent the formation of anaphase bridges and facilitate the proper segregation of sister chromatids. Irradiation-induced γH2AX foci persist for hours in M phase somatic cells. However, we observed that anaphase bridges formed in a significant fraction of mouse zygotes irradiated during mitosis. Additionally, γH2AX signals in M phase zygotes peaked 30 min after irradiation and subsequently reduced with a half-life within 1-2 h. These results suggest that the DNA repair system may operate efficiently in M phase zygotes following irradiation, leading to the frequent formation of anaphase bridges. The absence of H2AX promoted the successful segregation of sister chromatids and enhanced the development of embryos to the blastocyst stage. The DNA repair system may be differentially regulated during the M phase of the first cell cycle to ensure the immediate elimination of damaged zygotes, thereby efficiently preventing transmission of mutations to subsequent generations.

Targeting proliferating cell nuclear antigen (PCNA) for cancer therapy

Proliferating cell nuclear antigen (PCNA) is an essential scaffold protein in many cellular processes. It is best known for its role as a DNA sliding clamp and processivity factor during DNA replication, which has been extensively reviewed by others. However, the importance of PCNA extends beyond its DNA-associated functions in DNA replication, chromatin remodelling, DNA repair and DNA damage tolerance (DDT), as new non-canonical roles of PCNA in the cytosol have recently been identified. These include roles in the regulation of immune evasion, apoptosis, metabolism, and cellular signalling. The diverse roles of PCNA are largely mediated by its myriad protein interactions, and its centrality to cellular processes makes PCNA a valid therapeutic anticancer target. PCNA is expressed in all cells and plays an essential role in normal cellular homeostasis; therefore, the main challenge in targeting PCNA is to selectively kill cancer cells while avoiding unacceptable toxicity to healthy cells. This chapter focuses on the stress-related roles of PCNA, and how targeting these PCNA roles can be exploited in cancer therapy.

A Novel 2-Methoxyestradiol Derivative: Disrupting Mitosis Inhibiting Cell Motility and Inducing Apoptosis in HeLa Cells In Vitro

The clinical application of 2-methoxyestradiol (2ME) in cancer therapy has been limited by its low solubility and rapid metabolism. Derivatives of 2ME have been synthesised to enhance bioavailability and decrease hepatic metabolism. Compound 4a, an analog of 2ME, has demonstrated exceptional pharmacological activity, in addition to promising pharmacokinetic profile. Our study, therefore, aimed at exploring the anticancer effects of 4a on the cervical cancer cell line, HeLa. Compound 4a exhibited a significant and dose-dependent antimetastatic and antiinvasive impact on HeLa cells, as determined by wound-healing and Boyden chamber assays, respectively. Hoechst/Propidium iodide (HOPI) double staining showcased a substantial induction of apoptosis via 4a, with minimal necrotic effect. Flow cytometry revealed a significant G2/M phase arrest, accompanied by a noteworthy rise in the sub-G1 cell population, indicating apoptosis, 18 h post-treatment. Moreover, a cell-independent tubulin polymerisation assay illustrated compound 4a's ability to stabilise microtubules by promoting tubulin polymerisation. Molecular modelling experiments depicted that 4a interacts with the colchicine-binding site, nestled between the α and β tubulin dimers. Furthermore, 4a displayed an affinity for binding to and activating ER-α, as demonstrated by the luciferase reporter assay. These findings underscore the potential of 4a in inhibiting HPV18+ cervical cancer proliferation and cellular motility.

Weakened APC/C activity at mitotic exit drives cancer vulnerability to KIF18A inhibition

The efficacy of current antimitotic cancer drugs is limited by toxicity in highly proliferative healthy tissues. A cancer-specific dependency on the microtubule motor protein KIF18A therefore makes it an attractive therapeutic target. Not all cancers require KIF18A, however, and the determinants underlying this distinction remain unclear. Here, we show that KIF18A inhibition drives a modest and widespread increase in spindle assembly checkpoint (SAC) signaling from kinetochores which can result in lethal mitotic delays. Whether cells arrest in mitosis depends on the robustness of the metaphase-to-anaphase transition, and cells predisposed with weak basal anaphase-promoting complex/cyclosome (APC/C) activity and/or persistent SAC signaling through metaphase are uniquely sensitive to KIF18A inhibition. KIF18A-dependent cancer cells exhibit hallmarks of this SAC:APC/C imbalance, including a long metaphase-to-anaphase transition, and slow mitosis overall. Together, our data reveal vulnerabilities in the cell division apparatus of cancer cells that can be exploited for therapeutic benefit.

Microtubule destabilising activity of selected 7-methoxy-2-phenylbenzo[b]furan derivative against primary and metastatic melanoma cells

Herein, we report the results of anticancer screening of two 2-phenylbenzo[b]furan derivatives functionalised at the 3-position with 4-hydroxy-3,5-dimethoxybenzoyl (BF2) or 3,4,5-trimethoxybenzoyl (BF3) against 60 different cancer cell lines. The results confirmed the anticancer potential of the tested compounds against different cancer cell types, especially colon cancer, brain cancer and melanoma. BF3 was defined as the most potent (also as a tubulin polymerisation inhibitor). Its anticancer activity against melanoma cell lines that originated from different stages, i.e., primary skin-derived A375 and metastatic WM9/MDA-MB-435S, was evaluated (as the clinical success of melanoma therapy strictly depends on the disease stage). Moreover, to determine the BF3 mode of action and its effect on cell proliferation, intracellular microtubule networks, cell cycle phase distribution and apoptosis were evaluated. Our study revealed that BF3 inhibited cell proliferation in a dose-dependent manner, with IC50 yielding 0.09 ± 0.01 μM, 0.11 ± 0.01 μM and 0.18 ± 0.05 μM for A375, MDA-MB435S and WM9, respectively. The strong antiproliferative activity of compound BF3 correlated well with its inhibitory effect on tubulin polymerisation. Molecular docking proved that BF3 belongs to the colchicine binding site inhibitors (CBSIs), and experimental studies revealed that it disturbs cell cycle progression leading to G2/M arrest and apoptosis.

p53 and p21 dynamics encode single-cell DNA damage levels, fine-tuning proliferation and shaping population heterogeneity

Cells must accurately and quickly detect DNA damage through a set of checkpoint mechanisms that enable repair and control proliferation. Heterogeneous levels of cellular stress and noisy signaling processes can lead to phenotypic variability but little is known about their role in underlying proliferation heterogeneity. Here we study two previously published single cell datasets and find that cells encode heterogeneous levels of endogenous and exogenous DNA damage to shape proliferation heterogeneity at the population level. Using a comprehensive time series analysis of short- and long-term signaling dynamics of p53 and p21, we show that DNA damage levels are quantitatively translated into p53 and p21 signal parameters in a gradual manner. Analyzing instantaneous proliferation and signaling differences among equally-radiated cells, we identify time-localized changes in the period of p53 pulses that drive cells out of a low proliferative state. Our findings suggest a novel role of the p53-p21 network in quantitatively encoding DNA damage strength and fine-tuning proliferation trajectories.

Mitotic Kinase Inhibitors as Therapeutic Interventions for Prostate Cancer: Evidence from In Vitro Studies

Prostate cancer is one of the devastating diseases characterized by genetic changes leading to uncontrolled growth and metastasis of the cells of the prostate gland and affects men worldwide. Conventional hormonal and chemotherapeutic agents are effective in mitigating the disease if diagnosed at an early stage. All dividing eukaryotic cells require mitotic progression for the maintenance of genomic integrity in progeny populations. The protein kinases, upon activation and de-activation in an ordered fashion, lead to spatial and temporal regulation of the cell division process. The entry into mitosis along with the progression into sub-phases of mitosis is ensured due to the activity of mitotic kinases. These kinases include Polo-Like-Kinase 1 (PLK1), Aurora kinases, and Cyclin-Dependent- Kinase 1 (CDK1), among others. The mitotic kinases, among others, are usually overexpressed in many cancers and can be targeted using small molecule inhibitors to reduce the effects of these regulators on mechanisms, such as regulation of genomic integrity and mitotic fidelity. In this review, we attempted to discuss the appropriate functions of mitotic kinases revealed through cell culture studies and the impact of their respective inhibitors derived in pre-clinical studies. The review is designed to elucidate the growing field of small molecule inhibitors and their functional screening or mode of action at the cellular and molecular level in the context of Prostate Cancer. Therefore, studies performed specifically on cells of Prostatic-origin are narrated in this review, culminating in a comprehensive view of the specific field of mitotic kinases that can be targeted for therapy of Prostate cancer.

In-silico identification of novel inhibitors for human Aurora kinase B form the ZINC database using molecular docking-based virtual screening

Introduction: Aurora kinase enzymes play critical functions in mammals. Aurora kinases are mitotic regulators that are involved in a variety of processes during cell division. The overexpression of these enzymes is associated with tumour formation and is symptomatic of clinical circumstances in cancer patients who have been diagnosed.

Materials and methods: The current study reports an in-silico virtual screening (VS) and molecular docking analysis of 2500 compounds retrieved from the ZINC database and five current clinical trial compounds against Aurora Kinase B using AutoDock Vina to identify potential inhibitors.

Results and discussion: The top six compounds that resulted from the screening were ZINC00190959, ZINC07889110, ZINC0088285, ZINC01404326, ZINC00882846 and ZINC08813187, which showed lower free energy of binding (FEB) against the target protein binding pocket. The FEB were as follows: -11.92, -11.85, -11.46, -11.33, -11.21 and -11.1 kcal/mol, using AutoDock, and -11.7, -11.5, -11.2, -11.0, -10.8 and -10.6 kcal/mol for AutoDock Vina, respectively. These findings were superior to those obtained with the co-crystallized ligand VX-680, with a -7.5 kcal/mol and the current clinical trial drug. Finally, using a VS and molecular docking approach, novel Aurora kinase B inhibitors were effectively identified from the ZINC database fulfilling the Lipinski rule of five with low FEB and functional molecular interactions with the target protein.

Conclusion: The findings suggest that the six compounds could be used as a potential agent for cancer treatments.

Graphical abstract

C118P exerted potent anti-tumor effects against melanoma with induction of G2/M arrest via inhibiting the expression of BUB1B

BACKGROUND

The incidence of melanoma rapidly increased in the past decades, and the clinical treatment of melanoma met huge challenges because of tumor heterogeneity and drug resistance. C118P, a novel tubulin polymerization inhibitor, exhibited strong anticancer effects in many tumors. However, there was no data regarding the potential effects of C118P in melanoma cells.

OBJECTIVE

To investigate of the efficacy and potential target of C118P in melanoma cells.

METHODS

Human melanoma cells were treated with C118P, followed by assessments of proliferation, apoptosis and cell cycle distribution. Subsequently, RNA sequencing was performed to further identify the drug targets of C118P in melanoma cells. GO analysis and protein-protein interaction networks analysis were used to screen the potential targets, and verified by a series of assays. Finally, the anti-growth activity of C118P was evaluated in A375-xenografted nude mice, and the expression of BUB1B (BUB1 mitotic checkpoint serine/threonine kinase B), Ki67 and Tunel were determined.

RESULTS

We found that C118P concentration-dependently inhibited proliferation of melanoma cells. Moreover, C118P simultaneously triggered dramatic G2/M arrest and apoptosis via independent mechanisms in melanoma cells in vitro. C118P exerted anti-melanoma effects by inducing potent G2/M arrest, which was mechanistically related to downregulation of the expression of BUB1B. Importantly, C118P inhibited the tumor growth in A375-xenografted nude, and increased the staining of Ki-67 and Tunel and suppressed the expression of BUB1B in melanoma tissues, which was consistent with in vitro study.

CONCLUSION

C118P might provide a novel strategy for the clinical treatment of melanoma by inhibition of BUB1B.

Trip13 Depletion in Liver Cancer Induces a Lipogenic Response Contributing to Plin2-Dependent Mitotic Cell Death

Aberrant energy metabolism and cell cycle regulation both critically contribute to malignant cell growth and both processes represent targets for anticancer therapy. It is shown here that depletion of the AAA+-ATPase thyroid hormone receptor interacting protein 13 (Trip13) results in mitotic cell death through a combined mechanism linking lipid metabolism to aberrant mitosis. Diminished Trip13 levels in hepatocellular carcinoma cells result in insulin-receptor-/Akt-pathway-dependent accumulation of lipid droplets, which act as functional acentriolar microtubule organizing centers disturbing mitotic spindle polarity. Specifically, the lipid-droplet-coating protein perilipin 2 (Plin2) is required for multipolar spindle formation, induction of DNA damage, and mitotic cell death. Plin2 expression in different tumor cells confers susceptibility to cell death induced by Trip13 depletion as well as treatment with paclitaxel, a spindle-interfering drug commonly used against different cancers. Thus, assessment of Plin2 levels enables the stratification of tumor responsiveness to mitosis-targeting drugs, including clinically approved paclitaxel and Trip13 inhibitors currently under development.

Cancer chemotherapy: insights into cellular and tumor microenvironmental mechanisms of action

Chemotherapy has historically been the mainstay of cancer treatment, but our understanding of what drives a successful therapeutic response remains limited. The diverse response of cancer patients to chemotherapy has been attributed principally to differences in the proliferation rate of the tumor cells, but there is actually very little experimental data supporting this hypothesis. Instead, other mechanisms at the cellular level and the composition of the tumor microenvironment appear to drive chemotherapy sensitivity. In particular, the immune system is a critical determinant of chemotherapy response with the depletion or knock-out of key immune cell populations or immunological mediators completely abrogating the benefits of chemotherapy in pre-clinical models. In this perspective, we review the literature regarding the known mechanisms of action of cytotoxic chemotherapy agents and the determinants of response to chemotherapy from the level of individual cells to the composition of the tumor microenvironment. We then summarize current work toward the development of dynamic biomarkers for response and propose a model for a chemotherapy sensitive tumor microenvironment.

Mechanisms of cancer cell death induction by paclitaxel: an updated review

Chemoresistance of cancer cells is a major problem in treating cancer. Knowledge of how cancer cells may die or resist cancer drugs is critical to providing certain strategies to overcome tumour resistance to treatment. Paclitaxel is known as a chemotherapy drug that can suppress the proliferation of cancer cells by inducing cell cycle arrest and induction of mitotic catastrophe. However, today, it is well known that paclitaxel can induce multiple kinds of cell death in cancers. Besides the induction of mitotic catastrophe that occurs during mitosis, paclitaxel has been shown to induce the expression of several pro-apoptosis mediators. It also can modulate the activity of anti-apoptosis mediators. However, certain cell-killing mechanisms such as senescence and autophagy can increase resistance to paclitaxel. This review focuses on the mechanisms of cell death, including apoptosis, mitotic catastrophe, senescence, autophagic cell death, pyroptosis, etc., following paclitaxel treatment. In addition, mechanisms of resistance to cell death due to exposure to paclitaxel and the use of combinations to overcome drug resistance will be discussed.

Targeting Microtubules for the Treatment of Heart Disease

Heart disease remains the leading cause of morbidity and mortality worldwide. With the advancement of modern technology, the role(s) of microtubules in the pathogenesis of heart disease has become increasingly apparent, though currently there are limited treatments targeting microtubule-relevant mechanisms. Here, we review the functions of microtubules in the cardiovascular system and their specific adaptive and pathological phenotypes in cardiac disorders. We further explore the use of microtubule-targeting drugs and highlight promising druggable therapeutic targets for the future treatment of heart diseases.

Which cell death modality wins the contest for photodynamic therapy of cancer?

Photodynamic therapy (PDT) was discovered more than 100 years ago. Since then, many protocols and agents for PDT have been proposed for the treatment of several types of cancer. Traditionally, cell death induced by PDT was categorized into three types: apoptosis, cell death associated with autophagy, and necrosis. However, with the discovery of several other regulated cell death modalities in recent years, it has become clear that this is a rather simple understanding of the mechanisms of action of PDT. New observations revealed that cancer cells exposed to PDT can pass through various non-conventional cell death pathways, such as paraptosis, parthanatos, mitotic catastrophe, pyroptosis, necroptosis, and ferroptosis. Nowadays, immunogenic cell death (ICD) has become one of the most promising ways to eradicate tumor cells by activation of the T-cell adaptive immune response and induction of long-term immunological memory. ICD can be triggered by many anti-cancer treatment methods, including PDT. In this review, we critically discuss recent findings on the non-conventional cell death mechanisms triggered by PDT. Next, we emphasize the role and contribution of ICD in these PDT-induced non-conventional cell death modalities. Finally, we discuss the obstacles and propose several areas of research that will help to overcome these challenges and lead to the development of highly effective anti-cancer therapy based on PDT.

Deep Reinforcement Learning-Based Progressive Sequence Saliency Discovery Network for Mitosis Detection In Time-Lapse Phase-Contrast Microscopy Images

Mitosis detection plays an important role in the analysis of cell status and behavior and is therefore widely utilized in many biological research and medical applications. In this article, we propose a deep reinforcement learning-based progressive sequence saliency discovery network (PSSD)for mitosis detection in time-lapse phase contrast microscopy images. By discovering the salient frames when cell state changes in the sequence, PSSD can more effectively model the mitosis process for mitosis detection. We formulate the discovery of salient frames as a Markov Decision Process (MDP)that progressively adjusts the selection positions of salient frames in the sequence, and further leverage deep reinforcement learning to learn the policy in the salient frame discovery process. The proposed method consists of two parts: 1)the saliency discovery module that selects the salient frames from the input cell image sequence by progressively adjusting the selection positions of salient frames; 2)the mitosis identification module that takes a sequence of salient frames and performs temporal information fusion for mitotic sequence classification. Since the policy network of the saliency discovery module is trained under the guidance of the mitosis identification module, PSSD can comprehensively explore the salient frames that are beneficial for mitosis detection. To our knowledge, this is the first work to implement deep reinforcement learning to the mitosis detection problem. In the experiment, we evaluate the proposed method on the largest mitosis detection dataset, C2C12-16. Experiment results show that compared with the state-of-the-arts, the proposed method can achieve significant improvement for both mitosis identification and temporal localization on C2C12-16.

The Cationic Amphiphilic Drug Hexamethylene Amiloride Eradicates Bulk Breast Cancer Cells and Therapy-Resistant Subpopulations with Similar Efficiencies

The resistance of cancer cell subpopulations, including cancer stem cell (CSC) populations, to apoptosis-inducing chemotherapeutic agents is a key barrier to improved outcomes for cancer patients. The cationic amphiphilic drug hexamethylene amiloride (HMA) has been previously demonstrated to efficiently kill bulk breast cancer cells independent of tumor subtype or species but acts poorly toward non-transformed cells derived from multiple tissues. Here, we demonstrate that HMA is similarly cytotoxic toward breast CSC-related subpopulations that are resistant to conventional chemotherapeutic agents, but poorly cytotoxic toward normal mammary stem cells. HMA inhibits the sphere-forming capacity of FACS-sorted human and mouse mammary CSC-related cells in vitro, specifically kills tumor but not normal mammary organoids ex vivo, and inhibits metastatic outgrowth in vivo, consistent with CSC suppression. Moreover, HMA inhibits viability and sphere formation by lung, colon, pancreatic, brain, liver, prostate, and bladder tumor cell lines, suggesting that its effects may be applicable to multiple malignancies. Our observations expose a key vulnerability intrinsic to cancer stem cells and point to novel strategies for the exploitation of cationic amphiphilic drugs in cancer treatment.

The phosphatase CTDSPL2 is phosphorylated in mitosis and a target for restraining tumor growth and motility in pancreatic cancer

Carboxy-terminal domain (CTD) small phosphatase like 2 (CTDSPL2), also known as SCP4 or HSPC129, is a new member of the small CTD phosphatase (SCP) family and its role in cancers remains unclear. Here, we used a Phos-tag technique to screen a series of phosphatases and identified CTDSPL2 as a mitotic regulator. We demonstrated that CTDSPL2 was phosphorylated at T86, S104, and S134 by cyclin-dependent kinase 1 (CDK1) in mitosis. Depletion of CTDSPL2 led to mitotic defects and prolonged mitosis. Resultantly, CTDSPL2 deletion restrained proliferation, migration, and invasion in pancreatic cancer cells. We further confirmed the dominant negative effects of a phosphorylation-deficient mutant form of CTDSPL2, implying the biological significance of CTDSPL2 mitotic phosphorylation. Moreover, RT² cell cycle array analysis revealed p21 and p27 as downstream regulators of CTDSPL2, and inhibition of p21 and/or p27 partially rescued the phenotype in CTDSPL2-deficient cell lines. Importantly, both CTDSPL2 depletion and phosphorylation-deficient mutant CTDSPL2 hindered tumor growth in xenograft models. Together, our findings for the first time highlight the novel role of CTDSPL2 in regulating cell mitosis, proliferation and motility in pancreatic cancer and point out the implications of CTDSPL2 in regulating two critical cell cycle participants (p21 and p27), providing an alternative molecular target for pancreatic cancer treatment.

Synchronization of HeLa Cells to Mitotic Subphases

The cell cycle is a series of events leading to cell replication. When plated at low cell densities in serum-containing medium, cultured cells start to proliferate, moving through the four phases of the cell cycle: G1, S, G2, and M. Mitosis is the most dynamic period of the cell cycle, involving a major reorganization of virtually all cell components. Mitosis is further divided into prophase, prometaphase, metaphase, anaphase, and telophase, which can be easily distinguished from one another by protein markers and/or comparing their chromosome morphology under fluorescence microscope. The progression of the cell cycle through these mitotic subphases is tightly regulated by complicated molecular mechanisms. Synchronization of cells to the mitotic subphases is important for understanding these molecular mechanisms. Here, we describe a protocol to synchronize Hela cells to prometaphase, metaphase, and anaphase/telophase. In this protocol, Hela cells are first synchronized to the early S phase by a double thymidine block. Following the release of the block, the cells are treated with nocodazole, MG132, and blebbistatin to arrest them at prometaphase, metaphase, and anaphase/telophase, respectively. Successful synchronization is assessed using Western blot and fluorescence microscopy.

Cell Cycle Progression and Synchronization: An Overview

The cell cycle is the series of events that take place in a cell that drives it to divide and produce two new daughter cells. Through more than 100 years of efforts by scientists, we now have a much clearer picture of cell cycle progression and its regulation. The typical cell cycle in eukaryotes is composed of the G1, S, G2, and M phases. The M phase is further divided into prophase, prometaphase, metaphase, anaphase, telophase, and cytokinesis. Cell cycle progression is mediated by cyclin-dependent kinases (Cdks) and their regulatory cyclin subunits. However, the driving force of cell cycle progression is growth factor-initiated signaling pathways that controls the activity of various Cdk-cyclin complexes. Most cellular events, including DNA duplication, gene transcription, protein translation, and post-translational modification of proteins, occur in a cell-cycle-dependent manner. To understand these cellular events and their underlying molecular mechanisms, it is desirable to have a population of cells that are traversing the cell cycle synchronously. This can be achieved through a process called cell synchronization. Many methods have been developed to synchronize cells to the various phases of the cell cycle. These methods could be classified into two groups: synchronization methods using chemical inhibitors and synchronization methods without using chemical inhibitors. All these methods have their own merits and shortcomings.

Design, structure-activity relationship study and biological evaluation of the thieno[3,2-c]isoquinoline scaffold as a potential anti-cancer agent

Several derivatives of a series that share a thienoisoquinoline scaffold have demonstrated potent activity against cancer cell lines A549, HeLa, HCT-116, and MDA-MB-231 in the submicromolar concentration range. Structure-activity relationship (SAR) studies on a range of derivatives aided in identifying key pharmacophores in the lead compound. A series of compounds have been identified as the most promising with submicromolar IC₅₀ values against a lung cancer cell line (A549). Microscopy studies of cancer cells treated with the lead compound revealed that it causes mitotic arrest and disrupts microtubules. Further evaluation via an in vitro microtubule polymerization assay and competition studies indicate that the lead compound binds to tubulin via the colchicine site.

Candidate oncogene circularNOP10 mediates gastric cancer progression by regulating miR-204/SIRT1 pathway

Background

The role of circular RNA (circRNA) in gastric cancer (GC) is attracting increasing attention. CircNOP10 (hsa_circ-0034351) has been reported to be upregulated in human GC tissue. However, the biological role and mechanism of circNOP10 in GC remain unknown.

Methods

Circular RNA expression profile of GC was detected based on microarray, and circNOP10 was identified for the subsequent investigation. Clinical samples of GC tissue and patient blood were obtained from the Zhongda Hospital, Southeast University. The different degraded GC cell lines were presented in our laboratory. The function and mechanism of circNOP10 in GC were investigated using Western blot, qRT-PCR, flow cytometry, in situ hybridization and pull down experiment.

Results

The results indicated that increased circNOP10 in GC tissue was involved in tumor stage and prognosis. In addition, circNOP10 sponged microRNA-24 (miR-204)-mediated biological processes through sirtuin 1 (SIRT1), which further confirmed that the circNOP10/miR-204/SIRT1 pathway promoted proliferation and migration as well as epithelial-mesenchymal transition (EMT) through the NF-κβ pathway in GC cell lines.

Conclusions

Candidate oncogene circNOP10 mediated GC cell proliferation, arrest cell cycle in G₂/M phase, induced cell apoptosis, enhanced tumor metastasis, as well as EMT by activating the miR-204/SIRT1 pathway, suggesting that it may serve as a potential biomarker in GC therapy.

Mechanisms by Which Kinesin-5 Motors Perform Their Multiple Intracellular Functions

Bipolar kinesin-5 motor proteins perform multiple intracellular functions, mainly during mitotic cell division. Their specialized structural characteristics enable these motors to perform their essential functions by crosslinking and sliding apart antiparallel microtubules (MTs). In this review, we discuss the specialized structural features of kinesin-5 motors, and the mechanisms by which these features relate to kinesin-5 functions and motile properties. In addition, we discuss the multiple roles of the kinesin-5 motors in dividing as well as in non-dividing cells, and examine their roles in pathogenetic conditions. We describe the recently discovered bidirectional motility in fungi kinesin-5 motors, and discuss its possible physiological relevance. Finally, we also focus on the multiple mechanisms of regulation of these unique motor proteins.

Future prospects for mitosis-targeted antitumor therapies

Dysregulation of cell cycle progression is a hallmark of cancer cells. In recent years, efforts have been devoted to the development of new therapies that target proteins involved in cell cycle regulation and mitosis. Novel targeted antimitotic drugs include inhibitors of aurora kinase family, polo-like kinase 1, Mps1, Eg5, CENP-5 and the APC/cyclosome complex. While certain new inhibitors reached the clinical trial stage, most were discontinued due to negative results. However, these therapies should not be readily dismissed. Based on recent advances concerning their mechanisms of action, new strategies could be devised to increase their efficacy and promote further clinical trials. Here we discuss three main lines of action to empower these therapeutic approaches: increasing cell death signals during mitotic arrest, targeting senescent cells and facilitating antitumor immune response through immunogenic cell death (ICD).

Forcing dividing cancer cells to die; low-dose drug combinations to prevent spindle pole clustering

Mitosis, under the control of the microtubule-based mitotic spindle, is an attractive target for anti-cancer treatments, as cancer cells undergo frequent and uncontrolled cell divisions. Microtubule targeting agents that disrupt mitosis or single molecule inhibitors of mitotic kinases or microtubule motors kill cancer cells with a high efficacy. These treatments have, nevertheless, severe disadvantages: they also target frequently dividing healthy tissues, such as the haematopoietic system, and they often lose their efficacy due to primary or acquired resistance mechanisms. An alternative target that has emerged in dividing cancer cells is their ability to "cluster" the poles of the mitotic spindle into a bipolar configuration. This mechanism is necessary for the specific survival of cancer cells that tend to form multipolar spindles due to the frequent presence of abnormal centrosome numbers or other spindle defects. Here we discuss the recent development of combinatorial treatments targeting spindle pole clustering that specifically target cancer cells bearing aberrant centrosome numbers and that have the potential to avoid resistance mechanism due their combinatorial nature.

HNRNP A1 Promotes Lung Cancer Cell Proliferation by Modulating VRK1 Translation

THeterogeneous nuclear ribonucleoprotein (HNRNP) A1 is the most abundant and ubiquitously expressed member of the HNRNP protein family. In recent years, it has become more evident that HNRNP A1 contributes to the development of neurodegenerative diseases. However, little is known about the underlying role of HNRNP A1 in cancer development. Here, we report that HNRNP A1 expression is significantly increased in lung cancer tissues and is negatively correlated with the overall survival of patients with lung cancer. Additionally, HNRNP A1 positively regulates vaccinia-related kinase 1 (VRK1) translation via binding directly to the 3′ untranslated region (UTR) of VRK1 mRNA, thus increasing cyclin D1 (CCND1) expression by VRK1-mediated phosphorylation of the cAMP response element–binding protein (CREB). Furthermore, HNRNP A1 binding to the cis-acting region of the 3′UTR of VRK1 mRNA contributes to increased lung cancer cell proliferation. Thus, our study unveils a novel role of HNRNP A1 in lung carcinogenesis via post-transcriptional regulation of VRK1 expression and suggests its potential as a therapeutic target for patients with lung cancer.

Preclinical small molecule WEHI-7326 overcomes drug resistance and elicits response in patient-derived xenograft models of human treatment-refractory tumors

Targeting cell division by chemotherapy is a highly effective strategy to treat a wide range of cancers. However, there are limitations of many standard-of-care chemotherapies: undesirable drug toxicity, side-effects, resistance and high cost. New small molecules which kill a wide range of cancer subtypes, with good therapeutic window in vivo, have the potential to complement the current arsenal of anti-cancer agents and deliver improved safety profiles for cancer patients. We describe results with a new anti-cancer small molecule, WEHI-7326, which causes cell cycle arrest in G2/M, cell death in vitro, and displays efficacious anti-tumor activity in vivo. WEHI-7326 induces cell death in a broad range of cancer cell lines, including taxane-resistant cells, and inhibits growth of human colon, brain, lung, prostate and breast tumors in mice xenografts. Importantly, the compound elicits tumor responses as a single agent in patient-derived xenografts of clinically aggressive, treatment-refractory neuroblastoma, breast, lung and ovarian cancer. In combination with standard-of-care, WEHI-7326 induces a remarkable complete response in a mouse model of high-risk neuroblastoma. WEHI-7326 is mechanistically distinct from known microtubule-targeting agents and blocks cells early in mitosis to inhibit cell division, ultimately leading to apoptotic cell death. The compound is simple to produce and possesses favorable pharmacokinetic and toxicity profiles in rodents. It represents a novel class of anti-cancer therapeutics with excellent potential for further development due to the ease of synthesis, simple formulation, moderate side effects and potent in vivo activity. WEHI-7326 has the potential to complement current frontline anti-cancer drugs and to overcome drug resistance in a wide range of cancers.

Synthesis and Anticancer Activity of Mitotic-Specific 3,4-Dihydropyridine-2(1H)-thiones

Most anticancer drugs target mitosis as the most crucial and fragile period of rapidly dividing cancer cells. However the limitations of classical chemotherapeutics drive the search for new more effective and selective compounds. For this purpose structural modifications of the previously characterized pyridine aalog (S1) were incorporated aiming to obtain an antimitotic inhibitor of satisfactory and specific anticancer activity. Structure-activity relationship analysis of the compounds against a panel of cancer cell lines allowed to select a compound with a thiophene ring at C5 of a 3,4-dihydropyridine-2(1H)-thione (S22) with promising antiproliferative activity (IC50 equal 1.71 ± 0.58 µM) and selectivity (SI = 21.09) against melanoma A375 cells. Moreover, all three of the most active compounds from the antiproliferative study, namely S1, S19 and S22 showed better selectivity against A375 cells than reference drug, suggesting their possible lower toxicity and wider therapeutic index. As further study revealed, selected compounds inhibited tubulin polymerization via colchicine binding site in dose dependent manner, leading to aberrant mitotic spindle formation, cell cycle arrest and apoptosis. Summarizing, the current study showed that among obtained mitotic-specific inhibitors analogue with thiophene ring showed the highest antiproliferative activity and selectivity against cancer cells.

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.

Covalent cell surface recruitment of chemotherapeutic polymers enhances selectivity and activity

Synthetic macromolecular chemotherapeutics inspired by host defence peptides can disrupt cell membranes and are emerging as agents for the treatment of cancer and infections. However, their off-target effects remain a major unmet challenge. Here we introduce a covalent recruitment strategy, whereby metabolic oligosaccharide engineering is used to label targeted cells with azido glycans, to subsequently capture chemotherapeutic polymers by a bio-orthogonal click reaction. This results in up to 10-fold reduction in EC50 and widening of the therapeutic window. Cell death is induced by not only membrane leakage, but also by apoptosis due to the conjugated chemotherapeutic being internalised by glycan recycling. Covalent recruitment also lead to increased penetration and significant cell death in a 3-D tumour model in just 3 hours, whereas doxorubicin required 24 hours. This conceptual approach of 'engineering cells to capture polymers' rather than 'engineering polymers to target cells' will bring new opportunities in non-traditional macromolecular therapeutics.

Biomolecular Condensates and Cancer

Malignant transformation is characterized by dysregulation of diverse cellular processes that have been the subject of detailed genetic, biochemical, and structural studies, but only recently has evidence emerged that many of these processes occur in the context of biomolecular condensates. Condensates are membrane-less bodies, often formed by liquid-liquid phase separation, that compartmentalize protein and RNA molecules with related functions. New insights from condensate studies portend a profound transformation in our understanding of cellular dysregulation in cancer. Here we summarize key features of biomolecular condensates, note where they have been implicated-or will likely be implicated-in oncogenesis, describe evidence that the pharmacodynamics of cancer therapeutics can be greatly influenced by condensates, and discuss some of the questions that must be addressed to further advance our understanding and treatment of cancer.

Novel system in vitro of classifying oral carcinogenesis based on feature extraction for gray-level co-occurrence matrix using scanned laser pico projector

Oral cancer is among the top 10 causes of death due to cancer worldwide. The prognosis for oral cancer patients is not good, with a 5-year survival rate of only 50%. Earlier and more precise classification will help clinicians make a diagnosis and patients survive. With the advancement of technology, computer-aided detection methods are used to help clinicians form therapy strategies. Gray-level co-occurrence matrix (GLCM) feature extraction of images describing the spatial distribution of gray levels is widely used in medical imaging analysis. Scanned laser pico projector (SLPP) has advantages such as high intensity, directivity, coherence, and mono-color with low bandwidth. In this study, GLCM feature extraction and SLPP reflex images were combined to make a small, non-staining, noninvasive classification system. According to the various image characteristics in oral carcinogenesis, SLPP reflex images better define the borders and three-dimensional structures and provide effective GLCM features such as contrast, energy, and homogeneity to classify carcinogenesis in dysplastic oral keratinocyte (DOK) and normal oral keratinocyte (NOK) cells. Moreover, it also reliably classifies highly metastatic (HSC-3) and tongue cancer (CAL-27) cells. A promising computer-aided classification system for oral cancer was developed to build a reliable intraoral examination system for in situ computer-aided diagnosis in normal clinics.

From Plant to Patient: Thapsigargin, a Tool for Understanding Natural Product Chemistry, Total Syntheses, Biosynthesis, Taxonomy, ATPases, Cell Death, and Drug Development

Thapsigargin, the first representative of the hexaoxygenated guaianolides, was isolated 40 years ago in order to understand the skin-irritant principles of the resin of the umbelliferous plant Thapsia garganica. The pronounced cytotoxicity of thapsigargin is caused by highly selective inhibition of the intracellular sarco-endoplasmic Ca²⁺-ATPase (SERCA) situated on the membrane of the endo- or sarcoplasmic reticulum. Thapsigargin is selective to the SERCA pump and to a minor extent the secretory pathway Ca²⁺/Mn²⁺ ATPase (SPCA) pump. Thapsigargin has become a tool for investigation of the importance of SERCA in intracellular calcium homeostasis. In addition, complex formation of thapsigargin with SERCA has enabled crystallization and structure determination of calcium-free states by X-ray crystallography. These results led to descriptions of the mechanism of action and kinetic properties of SERCA and other ATPases. Inhibition of SERCA depletes Ca²⁺ from the sarco- and endoplasmic reticulum provoking the unfolded protein response, and thereby has enabled new studies on the mechanism of cell death. Development of protocols for selective transformation of thapsigargin disclosed the chemistry and facilitated total synthesis of the molecule. Conversion of trilobolide into thapsigargin offered an economically feasible sustainable source of thapsigargin, which enables a future drug production. Principles for prodrug development were used by conjugating a payload derived from thapsigargin with a hydrophilic peptide selectively cleaved by proteases in the tumor. Mipsagargin was developed in order to obtain a drug for treatment of cancer diseases characterized by the presence of prostate specific membrane antigen (PSMA) in the neovascular tissue of the tumors. Even though mipsagargin showed interesting clinical effects the results did not encourage funding and consequently the attempt to register the drug has been abandoned. In spite of this disappointing fact, the research performed to develop the drug has resulted in important scientific discoveries concerning the chemistry, biosynthesis and biochemistry of sesquiterpene lactones, the mechanism of action of ATPases including SERCA, mechanisms for cell death caused by the unfolded protein response, and the use of prodrugs for cancer-targeting cytotoxins. The presence of toxins in only some species belonging to Thapsia also led to a major revision of the taxonomy of the genus.

Phase 1 dose escalation trial of volasertib in combination with decitabine in patients with acute myeloid leukemia

Polo-like kinase 1 (PLK1) regulates mitotic checkpoints and cell division. PLK1 overexpression is reported in numerous cancers, including acute myeloid leukemia (AML), and is associated with poor prognosis. Volasertib is a selective, potent cell-cycle kinase inhibitor that targets PLK to induce mitotic arrest and apoptosis. This phase 1 trial investigated the maximum tolerated dose (MTD), safety, pharmacokinetics, and anti-leukemic activity of volasertib in combination with decitabine in AML patients aged ≥ 65 years. Thirteen patients were treated with escalating volasertib doses (3 + 3 design; 300 mg, 350 mg, and 400 mg) plus standard-dose decitabine. Dose-limiting toxicity was reported in one patient in cycle 1; the MTD of volasertib in combination with decitabine was determined as 400 mg. The most common treatment-emergent adverse events were febrile neutropenia, pneumonia, and decreased appetite. Objective response rate was 23%. The combination was well tolerated, and the adverse event profile was in line with previous findings.

Large Scale Conversion of Trilobolide into the Payload of Mipsagargin: 8-O-(12-Aminododecanoyl)-8-O-Debutanoylthapsigargin

In spite of the impressing cytotoxicity of thapsigargin (Tg), this compound cannot be used as a chemotherapeutic drug because of general toxicity, causing unacceptable side effects. Instead, a prodrug targeted towards tumors, mipsagargin, was brought into clinical trials. What substantially reduces the clinical potential is the limited access to Tg and its derivatives and cost-inefficient syntheses with unacceptably low yields. Laser trilobum, which contains a structurally related sesquiterpene lactone, trilobolide (Tb), is successfully cultivated. Here, we report scalable isolation of Tb from L. trilobum and a transformation of Tb to 8-O-(12-aminododecanoyl)-8-O-debutanoylthapsigargin in seven steps. The use of cultivated L. trilobum offers an unlimited source of the active principle in mipsagargin.

Targeting aurora kinases as a potential prognostic and therapeutical biomarkers in pediatric acute lymphoblastic leukaemia

Aurora kinases (AURKA and AURKB) are mitotic kinases with an important role in the regulation of several mitotic events, and in hematological malignancies, AURKA and AURKB hyperexpression are found in patients with cytogenetic abnormalities presenting a unfavorable prognosis. The aim of this study was evaluated the mRNA expression profile of pediatric Acute Lymphoblastic Leukaemia (ALL) patients and the efficacy of two AURKA and AURKB designed inhibitors (GW809897X and GW806742X) in a leukemia cell line as a potential novel therapy for ALL patients. Cellular experiments demonstrated that both inhibitors induced cell death with caspase activation and cell cycle arrest, however only the GW806742X inhibitor decreased with more efficacy AURKA and AURKB expression in K-562 leukemia cells. In ALL patients both AURKA and AURKB showed a significant overexpression, when compared to health controls. Moreover, AURKB expression level was significant higher than AURKA in patients, and predicted a poorer prognosis with significantly lower survival rates. No differences were found in AURKA and AURKB expression between gene fusions, immunophenotypic groups, white blood cells count, gender or age. In summary, the results in this study indicates that the AURKA and AURKB overexpression are important findings in pediatric ALL, and designed inhibitor, GW806742X tested in vitro were able to effectively inhibit the gene expression of both aurora kinases and induce apoptosis in K-562 cells, however our data clearly shown that AURKB proves to be a singular finding and potential prognostic biomarker that may be used as a promising therapeutic target to those patients.

FoxM1 insufficiency hyperactivates Ect2-RhoA-mDia1 signaling to drive cancer

FoxM1 activates genes that regulate S-G2-M cell-cycle progression and, when overexpressed, is associated with poor clinical outcome in multiple cancers. Here we identify FoxM1 as a tumor suppressor in mice that, through its N-terminal domain, binds to and inhibits Ect2 to limit the activity of RhoA GTPase and its effector mDia1, a catalyst of cortical actin nucleation. FoxM1 insufficiency impedes centrosome movement through excessive cortical actin polymerization, thereby causing the formation of non-perpendicular mitotic spindles that missegregate chromosomes and drive tumorigenesis in mice. Importantly, low FOXM1 expression correlates with RhoA GTPase hyperactivity in multiple human cancer types, indicating that suppression of the newly discovered Ect2-RhoAmDia1 oncogenic axis by FoxM1 is clinically relevant. Furthermore, by dissecting the domain requirements through which FoxM1 inhibits Ect2 GEF activity, we provide mechanistic insight for the development of pharmacological approaches that target protumorigenic RhoA activity.

MKI-1, a Novel Small-Molecule Inhibitor of MASTL, Exerts Antitumor and Radiosensitizer Activities Through PP2A Activation in Breast Cancer

Although MASTL (microtubule-associated serine/threonine kinase-like) is an attractive target for anticancer treatment, MASTL inhibitors with antitumor activity have not yet been reported. In this study, we have presented a novel MASTL inhibitor, MKI-1, identified through in silico screening and in vitro analysis. Our data revealed that MKI-1 exerted antitumor and radiosensitizer activities in in vitro and in vivo models of breast cancer. The mechanism of action of MKI-1 occurred through an increase in PP2A activity, which subsequently decreased the c-Myc protein content in breast cancer cells. Moreover, the activity of MKI-1 in the regulation of MASTL-PP2A was validated in a mouse oocyte model. Our results have demonstrated a new small-molecule inhibitor of MASTL, MKI-1, which exerts antitumor and radiosensitizer activities through PP2A activation in breast cancer in vitro and in vivo.