Induction Of Mitotic Catastrophe Research Articles

Targeting the COMMD4–H2B protein complex in lung cancer

BackgroundLung cancer is the biggest cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) accounts for 85–90% of all lung cancers. Identification of novel therapeutic targets are required as drug resistance impairs chemotherapy effectiveness. COMMD4 is a potential NSCLC therapeutic target. The aims of this study were to investigate the COMMD4-H2B binding pose and develop a short H2B peptide that disrupts the COMMD4-H2B interaction and mimics COMMD4 siRNA depletion.MethodsMolecular modelling, in vitro binding and site-directed mutagenesis were used to identify the COMMD4-H2B binding pose and develop a H2B peptide to inhibit the COMMD4-H2B interaction. Cell viability, DNA repair and mitotic catastrophe assays were performed to determine whether this peptide can specially kill NSCLC cells.ResultsBased on the COMMD4-H2B binding pose, we have identified a H2B peptide that inhibits COMMD4-H2B by directly binding to COMMD4 on its H2B binding binding site, both in vitro and in vivo. Treatment of NSCLC cell lines with this peptide resulted in increased sensitivity to ionising radiation, increased DNA double-strand breaks and induction of mitotic catastrophe in NSCLC cell lines.ConclusionsOur data shows that COMMD4-H2B represents a novel potential NSCLC therapeutic target.

Phenethyl isothiocyanate and dasatinib combination synergistically reduces hepatocellular carcinoma growth via cell cycle arrest and oxeiptosis.

Introduction: Hepatocellular carcinoma (HCC) is the most common type of liver cancer, which is among the most lethal tumours. Combination therapy exploits multiple drugs to target key pathways synergistically to reduce tumour growth. Isothiocyanates have been shown to possess anticancer potential and to complement the anticancer activity of other compounds. This study aimed to investigate the potential of phenethyl isothiocyanate (PEITC) to synergise with dasatinib, improving its anticancer potential in HCC. Methods: MTT, 3D spheroids and clonogenic assays were used to assess the combination anti-tumour effect in vitro, whereas a murine syngeneic model was employed to evaluate the combination efficacy in vivo. DCFDA staining was employed to evaluate the production of reactive oxygen species (ROS), while flow cytometry and Western blot assays were used to elucidate the molecular mechanism of the synergistic activiy. Results: PEITC and dasatinib combination exhibited a synergistic effect in vitro and in vivo. The combination induced DNA damage and oxidative stress through the production of ROS, which led to the formation of a premature CDK1/Cyclin B1 complex associated with induction of mitotic catastrophe. Furthermore, ROS activated oxeiptosis, a caspase-independent form of programmed cell death. Conclusion: PEITC showed to enhance dasatinib action in treating HCC with increased production of ROS that induced cell cycle arrest followed by mitotic catastrophe, and to induce oxeiptosis. These results highlight the role that ITCs may have in cancer therapy as a complement of clinically approved chemotherapeutic drugs.

Perspectives and mechanisms for targeting mitotic catastrophe in cancer treatment.

Mitotic catastrophe is distinct from other cell death modes due to unique nuclear alterations characterized as multi and/or micronucleation. Mitotic catastrophe is a common and virtually unavoidable consequence during cancer therapy. However, a comprehensive understanding of mitotic catastrophe remains lacking. Herein, we summarize the anticancer drugs that induce mitotic catastrophe, including microtubule-targeting agents, spindle assembly checkpoint kinase inhibitors, DNA damage agents and DNA damage response inhibitors. Based on the relationships between mitotic catastrophe and other cell death modes, we thoroughly evaluated the roles played by mitotic catastrophe in cancer treatment as well as its advantages and disadvantages. Some strategies for overcoming its shortcomings while fully utilizing its advantages are summarized and proposed in this review. We also review how mitotic catastrophe regulates cancer immunotherapy. These summarized findings suggest that the induction of mitotic catastrophe can serve as a promising new therapeutic approach for overcoming apoptosis resistance and strengthening cancer immunotherapy.

Abstract P3-07-01: Mebendazole displays selective anti-breast cancer cytotoxicity via the induction of mitotic catastrophe

Abstract Metastatic breast cancer (mBC) is still an incurable disease and is responsible for the majority of breast cancer-related death, despite tremendous efforts spent on developing better regimens for mBC. Microtubule-targeting chemotherapy agents (MTAs) have been on the front lines of treating mBC. However, many of these drugs become ineffective following treatment, as a consequence of either primary or acquired resistance, which leads to refractory disease. Furthermore, failures of the first-line MTA treatment will negatively affect the effectiveness of the second- and third-line agents in the patients, as the overall response rates of the subsequent treatments are in a range of only ~12% to 35%. Thus, there is an urgent need for alternative MTAs that are significantly different in biological characteristics from those currently used MTAs for mBC therapy. For this purpose, we investigated Mebendazole (methyl 5-benzoyl-2-benzimidazole-carbamate (MEB), which binds different sites on the α/β-tubulin remote from the binding sites of other MTAs, for its potential against mBC cells. MEB has much lower in vivo toxicity than the other MTAs used to treat mBC and it can be orally administrated. We explored MEB for its effectiveness in anti-mBC cells with a panel of human breast normal and mBC cell lines. The data from clonogenic survival studies indicate that MEB delivers < 10-fold greater cytotoxicity toward mBC cells compared to normal mammary epithelial (HME) or benign breast tumor cells. Furthermore, the cytotoxicity in detected in mBC cells was attributed to the induction of mitotic catastrophe, as demonstrated by the increased mitotic cell population (cells with 4N-DNA content and Histon-H3-Ser10 phosphorylation) and concurrent nuclear fragmentation. In contrast, under the same dose range, MEB did not cause mitotic catastrophe in HME cells. In addition, our data also show that MEB is much more efficient in killing p53-deficient mBC cells than p53-proficient mBC cells for the same reason, induction of mitotic catastrophe, which suggest the protective function of p53 against MEB-induced mitotic catastrophe. Collectively, our data support a great potential for MEB as an innovative regimen for improving mBC treatment. Citation Format: Ying Yan, Janina Baranowska-Kortylewicz, Brendan Graff. Mebendazole displays selective anti-breast cancer cytotoxicity via the induction of mitotic catastrophe [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-07-01.

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.

Synthesis and Antitumor Activity of 2,3‐Diphenyl‐2H‐indazole Derivatives as Potent Antitubulin Agents

AbstractWe contribute with the design and synthesis of novel 2,3‐diphenyl‐2H‐indazole hybrids series (1–14). Compounds 4 and 6 had the highest antiproliferative activity against the cancer cell lines, HeLa, SK‐LU‐1, K‐562, PC‐3, SW620 and MCF‐7 (CC50 values from 3 to 5.4 μM). Their activity was also evaluated against a normal human cell line, showing their higher Selectivity Index against the cancer cell lines than the reference drug CA‐4. The inhibition of tubulin assembly by compounds 4 and 6 was determined using in vitro tubulin polymerization assay and Western Blotting. The induction of mitotic catastrophe was observed with immunofluorescence assays. Besides, it was demonstrated by flow cytometry that compounds 4 and 6 arrest HeLa cell cycle at G2/M and promote apoptotic cell death. The mitotic arrest was also associated with elevated levels of cyclin B1 protein. We have identified two hybrids that behave as microtubule‐destabilizing agents on different cancer cell lines.

Radiosensitization by the Selective Pan-FGFR Inhibitor LY2874455.

Ionizing radiation activates cytoprotective pathways in cancer cells. Fibroblast growth factor receptor (FGFR) is a key player in these pathways. Thus, FGFR signaling is a potential target to induce radiosensitization. LY2874455 is an orally administrable selective pan-FGFR inhibitor. However, the radiosensitizing effects of LY2874455 remain unclear. In this study, we addressed this issue by using radioresistant human cancer cell lines H1703 (FGFR1 mutant), A549 (FGFR1–4 wild-type), and H1299 (FGFR1–4 wild-type). At an X-ray dose corresponding to 50%-clonogenic survival as the endpoint, 100 nM LY2874455 increased the sensitivity of H1703, A549, and H1299 cells by 31%, 62%, and 53%, respectively. The combination of X-rays and LY2874455 led to a marked induction of mitotic catastrophe, a hallmark of radiation-induced cell death. Furthermore, combination treatment suppressed the growth of A549 xenografts to a significantly greater extent than either X-rays or the drug alone without noticeable toxicity. This is the first report to show the radiosensitizing effect of a selective pan-FGFR inhibitor. These data suggest the potential efficacy of LY2874455 as a radiosensitizer, warranting clinical validation.

Multiple actions of NMS-P715, the monopolar spindle 1 (MPS1) mitotic checkpoint inhibitor in liver fluke-associated cholangiocarcinoma cells

AimNMS-P715 is a potent inhibitor of monopolar spindle 1 (MPS1) mitotic checkpoint kinase. Overexpression of MPS1 is associated with short survival times in patients with cholangiocarcinoma (CCA). This study investigated the anti-cancer effects of NMS-P715 in human CCA cell lines. Main methodsKKU-100 and KKU-213A CCA cell lines were treated with NMS-P715 and cell viability was determined using MTT and colony formation assays. Inhibitory effects of NMS-P715 on cell cycle and apoptosis were evaluated using flow cytometry. Expression of underlying mechanism-related proteins was examined by Western blotting. Mitotic catastrophe was assessed by counting abnormal nuclei. Transwell assays were used to examine cell migration and invasion. Key findingsMolecular docking showed that the NMS-P715/MPS1 complex was driven by an induced-fit mechanism. We provide new evidence that NMS-P715 potently inhibited cell proliferation and colony formation in both CCA cell lines. This was accompanied by induction of G2/M arrest and the consequent induction of mitotic catastrophe, a process that occurs during defective mitosis. The recent study showed that NMS-P715 activated caspase-dependent apoptosis and autophagosome formation with an increase of LC3 A/B-II protein expression in CCA cell lines. NMS-P715 also greatly impeded cell migration and invasion in CCA cell lines. The combination of NMS-P715 and gemcitabine or cisplatin showed synergistic effects on CCA cell proliferation. SignificanceThis study revealed for the first time that NMS-P715 is a promising candidate for combating CCA owing via multiple actions and may be suitable for further development in a clinical study.

One therapeutic approach for triple-negative breast cancer: Checkpoint kinase 1 inhibitor AZD7762 combination with neoadjuvant carboplatin

Carboplatin treatment is associated with potential benefits in practice in the neoadjuvant chemotherapy for Triple-negative breast cancer (TNBC) patients. In order to enhance its anti-tumor effects, new concepts for successful combination therapy are needed. Here, we interestingly found that the combination treatment of carboplatin with the Chk1 inhibitor AZD7762 synergistically inhibits TNBC cell growth in multiple TNBC cell lines in vitro. Mechanistically, we proved that prolonged carboplatin-treated induce cell mitotic arrest, and cells would fail to initiate the G2-M transition following the inhibition of the Chk1 pathway, leading to accumulation of DNA lesions. With this drug-in-combination treatment, the incidence of mitotic catastrophes including spindle multipolarity and cytokinesis failure is remarkably enhanced, which subsequently drives tumor cells multinucleation, polyploidization and apoptosis. Thus, our findings not only propose Chk1 as a therapeutic target for combination therapy with DNA-damaging agents such as carboplatin in TNBC, but also highlight that the induction of mitotic catastrophe could be considered as an alternative strategy for TNBC therapy.

ATR Inhibition Induces CDK1-SPOP Signaling and Enhances Anti-PD-L1 Cytotoxicity in Prostate Cancer.

Despite significant benefit for other cancer subtypes, immune checkpoint blockade (ICB) therapy has not yet been shown to significantly improve outcomes for men with castration-resistant prostate cancer (CRPC). Prior data have shown that DNA damage response (DDR) deficiency, via genetic alteration and/or pharmacologic induction using DDR inhibitors (DDRi), may improve ICB response in solid tumors in part due to induction of mitotic catastrophe and innate immune activation. Discerning the underlying mechanisms of this DDRi-ICB interaction in a prostate cancer-specific manner is vital to guide novel clinical trials and provide durable clinical responses for men with CRPC. We treated prostate cancer cell lines with potent, specific inhibitors of ATR kinase, as well as with PARP inhibitor, olaparib. We performed analyses of cGAS-STING and DDR signaling in treated cells, and treated a syngeneic androgen-indifferent, prostate cancer model with combined ATR inhibition and anti-programmed death ligand 1 (anti-PD-L1), and performed single-cell RNA sequencing analysis in treated tumors. ATR inhibitor (ATRi; BAY1895433) directly repressed ATR-CHK1 signaling, activated CDK1-SPOP axis, leading to destabilization of PD-L1 protein. These effects of ATRi are distinct from those of olaparib, and resulted in a cGAS-STING-initiated, IFN-β-mediated, autocrine, apoptotic response in CRPC. The combination of ATRi with anti-PD-L1 therapy resulted in robust innate immune activation and a synergistic, T-cell-dependent therapeutic response in our syngeneic mouse model. This work provides a molecular mechanistic rationale for combining ATR-targeted agents with immune checkpoint blockade for patients with CRPC. Multiple early-phase clinical trials of this combination are underway.

The Targeting of MRE11 or RAD51 Sensitizes Colorectal Cancer Stem Cells to CHK1 Inhibition.

Simple SummaryThe ATR-CHK1 axis of the DNA damage response is crucial for the survival of most colorectal cancer stem cells (CRC-SCs), but a significant fraction of primary CRC-SCs either is resistant to ATR or CHK1 inhibitors or survives the abrogation of the ATR-CHK1 cascade despite an initial response. Here, we demonstrate that the targeting of RAD51 or MRE11 improves the sensitivity of primary CRC-SCs to the CHK1/2 inhibitor prexasertib by sequentially inducing replication stress, the abrogation of cell cycle checkpoints, and the emergence of mitotic defects. This results in the induction of mitotic catastrophe and CRC-SC killing via a caspase-dependent apoptosis.Cancer stem cells (CSCs) drive not only tumor initiation and expansion, but also therapeutic resistance and tumor relapse. Therefore, CSC eradication is required for effective cancer therapy. In preclinical models, CSCs demonstrated high capability to tolerate even extensive genotoxic stress, including replication stress, because they are endowed with a very robust DNA damage response (DDR). This favors the survival of DNA-damaged CSCs instead of their inhibition via apoptosis or senescence. The DDR represents a unique CSC vulnerability, but the abrogation of the DDR through the inhibition of the ATR-CHK1 axis is effective only against some subtypes of CSCs, and resistance often emerges. Here, we analyzed the impact of druggable DDR players in the response of patient-derived colorectal CSCs (CRC-SCs) to CHK1/2 inhibitor prexasertib, identifying RAD51 and MRE11 as sensitizing targets enhancing prexasertib efficacy. We showed that combined inhibition of RAD51 and CHK1 (via B02+prexasertib) or MRE11 and CHK1 (via mirin+prexasertib) kills CSCs by affecting multiple genoprotective processes. In more detail, these two prexasertib-based regimens promote CSC eradication through a sequential mechanism involving the induction of elevated replication stress in a context in which cell cycle checkpoints usually activated during the replication stress response are abrogated. This leads to uncontrolled proliferation and premature entry into mitosis of replication-stressed cells, followed by the induction of mitotic catastrophe. CRC-SCs subjected to RAD51+CHK1 inhibitors or MRE11+CHK1 inhibitors are eventually eliminated, and CRC-SC tumorspheres inhibited or disaggregated, via a caspase-dependent apoptosis. These results support further clinical development of these prexasertib-based regimens in colorectal cancer patients.

Invitro induction of mitotic catastrophe as a therapeutic approach for oral cancer using the ethanolic extract of Juniperus squamata.

Mitotic catastrophe, a cell death mechanism characterized by abnormal mitosis, has been regarded as a therapeutic approach for the development of anti‑cancer drug candidates. The aim of the present study was to investigate the potential effect of the ethanolic extract of Juniperus squamata(EEJS) on the occurrence of mitotic catastrophe in human oral cancer cell lines. The effect of EEJS on the occurrence of mitotic catastrophe was evaluated by measuring cytotoxicity, observing phase‑contrast or transmission electron microscope findings, evaluating the appearance of microtubule or chromosome abnormalities, and detecting the phosphorylation of histoneH3(Ser10). The apoptotic effect of EEJS was assessed by detecting cleaved PARP, analyzing the sub‑G1 population, AnnexinV‑FITC/PI double staining, western blot analysis, and the transient transfection of myeloid cell leukemia‑1(Mcl‑1) overexpression vectors. EEJS treatment was effective in inhibiting cell proliferation in human oral cancer cell lines. EEJS resulted in the enrichment of enlarged multinucleated cells, the disturbance of microtubule formation, and increased phosphorylation of histoneH3 (Ser10), which demonstrates the occurrence of mitotic catastrophe. Additionally, the multinucleated cells underwent apoptotic cell death in a cell context‑dependent manner, which was associated with the reduction of Mcl‑1 protein levels. Findings of the present study indicate that EEJS could be effective for treating human oral cancer by promoting mitotic catastrophe linked to apoptotic cell death.

A New Inhibitor of Tubulin Polymerization Kills Multiple Cancer Cell Types and Reveals p21-Mediated Mechanism Determining Cell Death after Mitotic Catastrophe.

Induction of mitotic catastrophe through the disruption of microtubules is an established target in cancer therapy. However, the molecular mechanisms determining the mitotic catastrophe and the following apoptotic or non-apoptotic cell death remain poorly understood. Moreover, many existing drugs targeting tubulin, such as vincristine, have reduced efficacy, resulting from poor solubility in physiological conditions. Here, we introduce a novel small molecule 2-aminoimidazoline derivative—OAT-449, a synthetic water-soluble tubulin inhibitor. OAT-449 in a concentration range from 6 to 30 nM causes cell death of eight different cancer cell lines in vitro, and significantly inhibits tumor development in such xenograft models as HT-29 (colorectal adenocarcinoma) and SK-N-MC (neuroepithelioma) in vivo. Mechanistic studies showed that OAT-449, like vincristine, inhibited tubulin polymerization and induced profound multi-nucleation and mitotic catastrophe in cancer cells. HeLa and HT-29 cells within 24 h of treatment arrested in G2/M cell cycle phase, presenting mitotic catastrophe features, and 24 h later died by non-apoptotic cell death. In HT-29 cells, both agents altered phosphorylation status of Cdk1 and of spindle assembly checkpoint proteins NuMa and Aurora B, while G2/M arrest and apoptosis blocking was consistent with p53-independent accumulation in the nucleus and largely in the cytoplasm of p21/waf1/cip1, a key determinant of cell fate programs. This is the first common mechanism for the two microtubule-dissociating agents, vincristine and OAT-449, determining the cell death pathway following mitotic catastrophe demonstrated in HT-29 cells.

The CHK1 inhibitor MU380 significantly increases the sensitivity of human docetaxel-resistant prostate cancer cells to gemcitabine through the induction of mitotic catastrophe.

As treatment options for patients with incurable metastatic castration‐resistant prostate cancer (mCRPC) are considerably limited, novel effective therapeutic options are needed. Checkpoint kinase 1 (CHK1) is a highly conserved protein kinase implicated in the DNA damage response (DDR) pathway that prevents the accumulation of DNA damage and controls regular genome duplication. CHK1 has been associated with prostate cancer (PCa) induction, progression, and lethality; hence, CHK1 inhibitors SCH900776 (also known as MK‐8776) and the more effective SCH900776 analog MU380 may have clinical applications in the therapy of PCa. Synergistic induction of DNA damage with CHK1 inhibition represents a promising therapeutic approach that has been tested in many types of malignancies, but not in chemoresistant mCRPC. Here, we report that such therapeutic approach may be exploited using the synergistic action of the antimetabolite gemcitabine (GEM) and CHK1 inhibitors SCH900776 and MU380 in docetaxel‐resistant (DR) mCRPC. Given the results, both CHK1 inhibitors significantly potentiated the sensitivity to GEM in a panel of chemo‐naïve and matched DR PCa cell lines under 2D conditions. MU380 exhibited a stronger synergistic effect with GEM than clinical candidate SCH900776. MU380 alone or in combination with GEM significantly reduced spheroid size and increased apoptosis in all patient‐derived xenograft 3D cultures, with a higher impact in DR models. Combined treatment induced premature mitosis from G1 phase resulting in the mitotic catastrophe as a prestage of apoptosis. Finally, treatment by MU380 alone, or in combination with GEM, significantly inhibited tumor growth of both PC339‐DOC and PC346C‐DOC xenograft models in mice. Taken together, our data suggest that metabolically robust and selective CHK1 inhibitor MU380 can bypass docetaxel resistance and improve the effectiveness of GEM in DR mCRPC models. This approach might allow for dose reduction of GEM and thereby minimize undesired toxicity and may represent a therapeutic option for patients with incurable DR mCRPC.

Boosting Replication and Penetration of Oncolytic Adenovirus by Paclitaxel Eradicate Peritoneal Metastasis of Gastric Cancer

Peritoneal metastasis is the most frequent form of distant metastasis and recurrence in gastric cancer, and the prognosis is extremely poor due to the resistance of systemic chemotherapy. Here, we demonstrate that intraperitoneal (i.p.) administration of a green fluorescence protein (GFP)-expressing attenuated adenovirus with oncolytic potency (OBP-401) synergistically suppressed the peritoneal metastasis of gastric cancer in combination with paclitaxel (PTX). OBP-401 synergistically suppressed the viability of human gastric cancer cells in combination with PTX. PTX enhanced the antitumor effect of OBP-401 due to enhanced viral replication in cancer cells. The combination therapy increased induction of mitotic catastrophe, resulting in accelerated autophagy and apoptosis. Peritoneally disseminated nodules were selectively visualized as GFP-positive spots by i.p. administration of OBP-401 in an orthotopic human gastric cancer peritoneal dissemination model. PTX enhanced the deep penetration of OBP-401 into the disseminated nodules. Moreover, a non-invasive in vivo imaging system demonstrated that the combination therapy of i.p. OBP-401 administration with PTX significantly inhibited growth of peritoneal metastatic tumors and the amount of malignant ascites. i.p. virotherapy with PTX may be a promising treatment strategy for the peritoneal metastasis of gastric cancer.

Mechanism of mitotic catastrophe and its role in anticancer therapy

The definition of mitotic catastrophe has been the subject of scientific discussion for over a decade. Initially, it was thought that mitotic catastrophe is one of the types of cell death occurring during aberrant mitosis. A number of studies carried out in recent years allowed for a better understanding of the function of this process. According to the definition proposed by the Nomenclature Committee on Cell Death in 2018, mitotic catastrophe is an oncosuppressive mechanism that inhibits the proliferation and/or survival of cells that are unable to complete mitosis by inducing cell death or initiating cellular senescence. Mitotic catastrophe is recognized based on unique nuclear changes, the presence of abnormal mitotic figures and several molecular alterations. It is believed that avoiding mitotic catastrophe by genetically unstable cells promotes their unlimited growth, which can lead to cancer transformation. Therefore, the induction of mitotic catastrophe seems to be a promising strategy for the prevention and treatment of cancer. However, despite the significant role of this process, the molecular events between aberrant mitosis and cell death are still not well understood. It can be assumed that a thorough understanding of signaling pathways linking mitotic catastrophe with cell death will enable the effective use of known inducers of mitotic catastrophe in the treatment of cancer and provide new therapeutic targets. The aim of this review is to present a morphological and functional definition of mitotic catastrophe and its potential role in anticancer therapy.

Mitotic catastrophe and p53-dependent senescence induction in T-cell malignancies exposed to nonlethal dosage of GL-V9.

Mitotic catastrophe of cancer cells induced by drugs is characterized by low dosage and low toxicity, representing a significant advantage in the cancer treatment. Effective therapeutic options are limited for T-cell malignancies patients who are still treated by high-dose multiagent chemotherapy, potentially followed by hematopoietic stem cell transplantation, highlighting the urgency for identification of more effective anti-T-cell malignancies drugs. The use of antineoplastic drugs which induced tumor cell mitotic catastrophe would be a new strategy for cancer therapy. Nevertheless, there is still no effective mitotic catastrophe agent in T-cell malignancies. Our study showed that nonlethal dosage (ND) of GL-V9 (5-hydroxy-8-methoxy-2-phenyl-7-(4-(pyrrolidin-1-yl) butoxy) 4 H-chromen-4-one) (2µM), a potential anticancer drug, not only attenuated cell growth and survival, but also arrested the cell cycle in G2/M phase and induced multipolar spindles, nuclear alterations (micronucleation and multinucleation), which are the most prominent morphological characteristics of mitotic catastrophe, in T-cell malignancies cell lines including Jurkat, HuT-102, and HuT-78. Moreover, ND GL-V9 could trigger DNA damage, and significantly influence several mitosis-associated proteins. Besides, results showed that ND GL-V9 increased the activity of senescence-associated β-galactosidase (SA-β-Gal) following the induction of mitotic catastrophe in Jurkat and HuT-102 cells with intact p53, while causing apoptosis in p53-deficient HuT-78 cells. We concluded that the anti-T-cell malignancies effects of ND GL-V9 and clarified the precise regulation in the process of mitosis under the action of GL-V9 in T-cell malignancies. Our data provided new evidence for the study of T-cell malignancies treatment associated with mitotic catastrophe and cellular senescence induction.

Mitochondrial fission promotes radiation-induced increase in intracellular Ca2+ level leading to mitotic catastrophe in mouse breast cancer EMT6 cells

Mitochondrial dynamics are crucial for cellular survival in response to various stresses. Previously, we reported that Drp1 promoted mitochondrial fission after x-irradiation and its inhibition resulted in reduced cellular radiosensitivity and mitotic catastrophe. However, the mechanisms of radiation-induced mitotic catastrophe related to mitochondrial fission remain unclear. In this study, we investigated the involvement of cellular ATP production, ROS generation, and Ca2+ levels in mitotic catastrophe in EMT6 cells. Knockdown of Drp1 and Fis1, which are mitochondrial fission regulators, resulted in elongated mitochondria and significantly attenuated cellular radiosensitivity. Reduced mitochondrial fission mainly decreased mitotic catastrophe rather than necrosis and apoptosis after irradiation. Cellular ATP contents in Drp1 and Fis1 knockdown cells were similar to those in control cells. N-acetylcysteine and 2-glucopyranoside ascorbic acid have no effect on mitotic catastrophe after irradiation. The cellular [Ca2+]i level increased after irradiation, which was completely suppressed by Drp1 and Fis1 inhibition. Furthermore, BAPTA-AM significantly reduced radiation-induced mitotic catastrophe, indicating that cellular Ca2+ is a key mediator of mitotic catastrophe induction after irradiation. These results suggest that mitochondrial fission is associated with radiation-induced mitotic catastrophe via cytosolic Ca2+ regulation.

Abstract 2979: Boosting replication and penetration of telomerase-specific replicative virus by paclitaxel induces synthetic lethality in peritoneal metastasis of gastric cancer

Abstract Background: Peritoneal metastasis is the most frequent form of distant metastasis and recurrence in gastric cancer and its prognosis is extremely poor. A promising result in phase III trial using intraperitoneal (i.p.) paclitaxel (PTX) for the peritoneal metastasis of gastric cancer has been reported in recent year; however, it is not sufficiently effective to eradicate disseminated gastric cancer. In this study, we investigated whether novel i.p. oncolytic virotherapy could be synthetically lethal with PTX for the peritoneal metastasis of gastric cancer. Methods: OBP-401 (TelomeScan) is a green fluorescence protein (GFP)-expressing attenuated adenovirus with oncolytic potency that is driven by telomerase promoter. We assessed its synergistic effect with PTX using human gastric cancer cell lines (GCIY and KATO III) and xenograft peritoneal metastasis model. The mechanism underlying the synergistic antitumor effect was evaluated by in vitro viral replication, induction of mitotic catastrophe, and in vivo viral penetration into disseminated nodules. Results: OBP-401 synergistically suppressed the viability of human gastric cancer cells in combination with PTX. PTX was synthetically lethal with OBP-401 by enhancing viral replication ability in cancer cells and the combination therapy increased mitotic catastrophe induction, resulted in accelerating autophagy and apoptosis. Peritoneally disseminated nodules were selectively visualized as GFP-positive spots by the i.p. administration of OBP-401 in the orthotopic human gastric cancer peritoneal dissemination model. And, PTX enhanced the penetration of OBP-401 deeply into the disseminated nodules. Moreover, non-invasive in vivo imaging system (IVIS) demonstrated that the combination therapy of i.p. OBP-401 administration with PTX significantly inhibited tumor growth of peritoneal metastasis and the amount of malignant ascites. Conclusions: Intraperitoneal virotherapy with PTX may be a promising treatment strategy for the peritoneal metastasis of gastric cancer. Clinical trials to obtain the proof of concept are warranted in peritoneally disseminated gastric cancer patients. Citation Format: Toshihiro Ogawa, Satoru Kikuchi, Wataru Ishikawa, Hiroshi Tazawa, Motoyasu Tabuchi, Shinji Kuroda, Kazuhiro Noma, Masahiko Nishizaki, Shunsuke Kagawa, Yasuo Urata, Toshiyoshi Fujiwara. Boosting replication and penetration of telomerase-specific replicative virus by paclitaxel induces synthetic lethality in peritoneal metastasis of gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2979.

Emodin Induces Death in Human Cervical Cancer Cells Through Mitotic Catastrophe

Anthraquinones, including emodin, are compounds with numerous pharmacological properties, including anticancer properties. The aim of this study experiment was to examine the effect of emodin, a natural compound present in the roots and rhizomes of Rheum palmatum, on the induction of mitotic catastrophe in cervical cancer cells. HeLa celIs were treated with different emodin concentrations for 48 h, and cell growth was measured with 3-(4-,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolyl. The cell-cycle distribution and the level of apoptosis were determined by means of flow cytometry, using annexin V-fluorescein isothiocyanate staining and propidium iodide. Morphological changes in the mitotic apparatus were evaluated using optical and confocal microscopy techniques. Emodin induced an increase in the number of polymorphonuclear cells, giant cells, cells with micronuclei, cells with abnormal mitosis and damaged spindle. The reorganization of F-actin depended on the concentration of emodin. With the increase in emodin concentration, inhibition of mitotic activity was demonstrated, which was manifested by a decrease in the mitotic index, mainly in metaphase of the mitotic process and an increase in the number of cells inhibited in the G2/M phase. At the same time, an increase in the number of apoptotic cells was found. Emodin leads to death of cervical cancer cells by induction of a mitotic catastrophe.