Arrest Of Tumor Cells Research Articles

Licorice extract inhibits growth of non-small cell lung cancer by down-regulating CDK4-Cyclin D1 complex and increasing CD8+ T cell infiltration

BackgroundTargeting tumor microenvironment (TME) may provide therapeutic activity and selectivity in treating cancers. Therefore, an improved understanding of the mechanism by which drug targeting TME would enable more informed and effective treatment measures. Glycyrrhiza uralensis Fisch (GUF, licorice), a widely used herb medicine, has shown promising immunomodulatory activity and anti-tumor activity. However, the molecular mechanism of this biological activity has not been fully elaborated.MethodsHere, potential active compounds and specific targets of licorice that trigger the antitumor immunity were predicted with a systems pharmacology strategy. Flow cytometry technique was used to detect cell cycle profile and CD8+ T cell infiltration of licorice treatment. And anti-tumor activity of licorice was evaluated in the C57BL/6 mice.ResultsWe reported the G0/G1 growth phase cycle arrest of tumor cells induced by licorice is related to the down-regulation of CDK4-Cyclin D1 complex, which subsequently led to an increased protein abundance of PD-L1. Further, in vivo studies demonstrated that mitigating the outgrowth of NSCLC tumor induced by licorice was reliant on increased antigen presentation and improved CD8+ T cell infiltration.ConclusionsBriefly, our findings improved the understanding of the anti-tumor effects of licorice with the systems pharmacology strategy, thereby promoting the development of natural products in prevention or treatment of cancers.

Chromosomal instability sensitizes patient breast tumors to multipolar divisions induced by paclitaxel.

Paclitaxel (Taxol) is a cornerstone of cancer treatment. However, its mechanism of cytotoxicity is incompletely understood and not all patients benefit from treatment. We show that patients with breast cancer did not accumulate sufficient intratumoral paclitaxel to induce mitotic arrest in tumor cells. Instead, clinically relevant concentrations induced multipolar mitotic spindle formation. However, the extent of early multipolarity did not predict patient response. Whereas multipolar divisions frequently led to cell death, multipolar spindles focused into bipolar spindles before division at variable frequency, and maintaining multipolarity throughout mitosis was critical to induce the high rates of chromosomal instability necessary for paclitaxel to elicit cell death. Increasing multipolar divisions in paclitaxel resulted in improved cytotoxicity. Conversely, decreasing paclitaxel-induced multipolar divisions reduced paclitaxel efficacy. Moreover, we found that preexisting chromosomal instability sensitized breast cancer cells to paclitaxel. Both genetic and pharmacological methods of inducing chromosomal instability were sufficient to increase paclitaxel efficacy. In patients, the amount of pretreatment chromosomal instability directly correlated with taxane response in metastatic breast cancer such that patients with a higher rate of preexisting chromosomal instability showed improved response to taxanes. Together, these results support the use of baseline rates of chromosomal instability as a predictive biomarker for paclitaxel response. Furthermore, they suggest that agents that increase chromosomal instability or maintain multipolar spindles throughout mitosis will improve the clinical utility of paclitaxel.

Synthesis, characterization, HSA/DNA binding, cytotoxicity study, and antimicrobial activity of new palladium(II) complexes with some esters of (S,S)-propylenediamine-N,N'-di-2-(3-methyl)butanoic acid

In this paper, we presented synthesis, characterization, HSA/DNA binding evaluation, in vitro cytotoxic activity and in vitro antimicrobial activity of three new ligands of general formula. R2-S,S-pddmb (L1-L3) and their corresponding palladium(II) complexes of general formula [PdCl2(R2-S,S-pddmb)] (R = n-propyl, n-butyl, n-pentyl; S,S-pddmb = (S,S)-propylenediamine-N,N'-di-2-(3-methyl)-butanoate). Ligands and complexes were characterized by elemental microanalysis, infrared, 1H and 13C NMR spectroscopy. The interactions of new palladium(II) complexes with human serum albumin (HSA) and calf thymus DNA (CT-DNA) were investigated using UV–Vis absorption and fluorescence spectroscopy. The high values of the binding constant, Kb, and the Stern-Volmer quenching constant, KSV, are the result of good binding of all complexes to HSA and CT-DNA. In vitro cytotoxic activity of these ligands and complexes was evaluated against four tumor cell lines, 4 T1, CT26, MDA-MD-468, HCT116 and mesenchymal stem cells (mMSC). C3 complex showed high cytotoxic activity against MDA-MD-468 cell line. Flow cytometry analysis showed that L3 ligand and the corresponding complex (C3) stimulated apoptosis of tumor cells via inhibition of expression of antiapoptotic Bcl-2 molecule. L3 ligand and C3 complex slowed down cell proliferation and arrested tumor cell in the G0/G1 phase by decreasing Cyclin-D expression and by increasing expression of P21. In vitro antimicrobial activity of ligands and complexes was also investigated. The testing was performed by microdilution method and minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) were determined. The testing was conducted against 12 microorganisms. The tested ligands and palladium(II) complexes showed selective and moderate activity.

TRAIL produced by SAM-1-activated CD4+ and CD8+ subgroup T cells induces apoptosis in human tumor cells through upregulation of death receptors

Bacterial superantigens potently activate conventional T-cells to induce massive cytokine production and mediate tumor cell death. To engineer superantigens for immunotherapy against tumors in clinic, we previously generated SAM-1, a staphylococcal enterotoxins C2 (SEC2) mutant, that exhibited significantly reduced toxicity but maintained the superantigen activity in animal models. This present study aimed to investigate whether SAM-1 activates T cells and induces apoptosis in human tumor cells. We found that SAM-1 induced the maturation of dendritic cells (DCs) with upregulating expression of the surface markers CD80, CD86 and HLA-DR, which secreted high levels of IL-12p70 by activating TLR2-NF-κB signaling pathways. SAM-1 could activate human CD4+ subgroup T cells and CD8+ subgroup T cells in the presence of mature dendritic cells (DCs), leading to the productions of cytokines TRAIL, IL-2, IFN-γ and TNF-α. We observed that TRAIL mediated the apoptosis and S-phase and G2/M-phase arrest in HGC-27 tumor cells via binding to upregulated death receptors DR4 and DR5. Using shRNA knockdown in HGC-27 cells or constitutive overexpression in ES2 cells for DR4 and DR5, we demonstrated the vital requirement of DR4 and DR5 in apoptosis of tumor cells in response to TRAIL secreted from SAM-1-activated T cells. Collectively, our results will facilitate better understanding of SAM-1-based immunotherapies for cancer.

Knockdown of SENP1 inhibits HIF-1α SUMOylation and suppresses oncogenic CCNE1 in Wilms tumor

Based on our initial bioinformatics finding of the upregulated expression of sentrin-specific protease 1 (SENP1) and cyclin E1 (CCNE1) in Wilms tumor, this study aimed to illustrate the molecular mechanism of SENP1 in Wilms tumor, which involved the hypoxia-inducible factor 1α (HIF-1α)/stanniocalcin-1 (STC1)/CCNE1 axis. Wilms tumor and adjacent normal tissues were clinically collected. Gain- and loss-of-function assays were performed to evaluate the effects of the regulatory axis on malignant phenotypes of Wilms tumor cells. A mouse model of Wilms tumor xenografts was further established for in vivo substantiation. Overexpression of CCNE1 and SENP1 occurred in Wilms tumor tissues and cells. Silencing SENP1 inhibited viability and enhanced cell-cycle arrest of Wilms tumor cells. SENP1 promoted STC1 expression and upregulated CCNE1 by driving the small ubiquitin-like modifier (SUMO)ylation of HIF-1α, which ultimately promoted the malignant phenotypes of Wilms tumor cells. It was further confirmed that silencing SENP1 downregulated the expression of CCNE1 and restricted tumorigenicity of Wilms tumor cells in vivo. Taken together, SENP1 elevated STC1 expression by driving the SUMOylation of HIF-1α, thereby upregulating the expression of CCNE1 and ultimately promoting the development of Wilms tumor.

Lipofection of Single Guide RNA Targeting MMP8 Decreases Proliferation and Migration in Lung Adenocarcinoma Cells.

Background and Objectives: Matrix metalloproteinases (MMP) have been implicated as major determinants of tumour growth and metastasis, which are considered two of the main hallmarks of cancer. The interaction of MMP8 and other signalling molecules within and adjacent tumoral tissues, including immune cells, are rather elusive, particularly of adenocarcinoma cell type. In this study, we aimed to investigate the role of MMP8 in non-small cell lung cancer proliferation and invasiveness potential. Materials and Methods: We individually lipofected with two different single guide RNA (sgRNAs) that specifically targeted on MMP8, with CRISPR-Cas 9 protein into the cells. Results: Our results clearly indicated that the lipofection of these complexes could lead to reduced ability of A549 cells to survive and proliferate to form colonies. In addition, when compared to non-transfected cells, the experimental cell groups receiving sgRNAs demonstrated relatively decreased migration rate, hence, wider wound gaps in scratch assay. The quantitative real time-polymerase chain reaction (qRT-PCR) demonstrated significant reduction in the MAP-K, survivin and PI3-K gene expression. MMP8 might have protective roles over tumour growth and spread in our body. Conclusions: The delivery of sgRNAs targeting on the MMP8 gene could induce tumour cell death and arrest cell migratory activity.

The lncRNA ADAMTS9-AS2 Regulates RPL22 to Modulate TNBC Progression via Controlling the TGF-β Signaling Pathway

BackgroundLong non-coding RNAs (lncRNAs) are key regulators of triple-negative breast cancer (TNBC) progression, but further work is needed to fully understand the functional relevance of these non-coding RNAs in this cancer type. Herein, we explored the functional role of the lncRNA ADAMTS9-AS2 in TNBC.MethodsNext-generation sequencing was conducted to compare the expression of different lncRNAs in TNBC tumor and paracancerous tissues, after which ADAMTS9-AS2differential expression in these tumor tissues was evaluated via qPCR. The functional role of this lncRNA was assessed by overexpressing it in vitro and in vivo. FISH and PCR were used to assess the localization of ADAMTS9-AS2within cells. Downstream targets of ADAMTS9-AS2 signaling were identified via RNA pulldown assays and transcriptomic sequencing.ResultsThe expression ofADAMTS9-AS2 was decreased in TNBC tumor samples (P < 0.05), with such downregulation being correlated with TNM stage, age, and tumor size. Overexpressing ADAMTS9-AS2 promoted the apoptotic death and cell cycle arrest of tumor cells in vitro and inhibited tumor growth in vivo. From a mechanistic perspective, ADAMTS9-AS2 was found to control the expression of RPL22 and to thereby modulate TGF-β signaling to control TNBC progression.ConclusionADAMTS9-AS2 controls the expression of RPL22 and thereby regulates TNBC malignancy via the TGF-β signaling pathway.

Design, synthesis, and biological evaluation of 3-(1-benzotriazole)-nor-β-lapachones as NQO1-directed antitumor agents

A series of novel 3-(1-benzotriazole)-nor-β-lapachones 5a–5l were synthesized as the NQO1-targeted anticancer agents. Most of these compounds displayed good antiproliferative activity against the breast cancer MCF-7, lung cancer A549 and hepatocellular carcinoma HepG2 cells in agreements with their NQO1 activity. Among them, compound 5k was identified as a favorable NQO1 substrate. It could activate the ROS production in a NQO1-dependent manner, arrest tumor cell cycle at G0/G1 phase, promote tumor cell apoptosis, and decrease the mitochondrial membrane potential. In HepG2 xenograft models, 5k significantly suppressed the tumor growth with no influences on animal body weights. Therefore, 5k could be a good lead for further anticancer drug developments.

Thiophene derivative-loaded nanoparticles mediate anticancer activity through the inhibition of kinases and microtubule assembly.

Different tetrahydrobenzo[b]thiophene derivatives were explored as new tubulin polymerization destabilizers to arrest tumor cell mitosis. A series of compounds incorporating the tetrahydrobenzo[b]thiophene scaffold were synthesized, and their biological activities were investigated. The cytotoxicity of each of the synthesized compounds was assessed against a range of cell lines. Specifically, the benzyl urea tetrahydrobenzo[b]thiophene derivative, 1-benzyl-3-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)urea (BU17), was identified as the most potent compound with broad-spectrum antitumor activity against several cancer cell lines. The potential mechanism(s) of action were investigated where dose-dependent G2/M accumulation and A549 cell cycle arrest were detected. Additionally, A549 cells treated with BU17 expressed enhanced levels of caspase 3 and 9, indicating the induction of apoptosis. Furthermore, it was found that BU17 inhibits WEE1 kinase and targets tubulin by blocking its polymerization. BU17 was also formulated into PLGA nanoparticles, and it was demonstrated that BU17-loaded nanoparticles could significantly enhance antitumor activity compared to the soluble counterpart.

GSK-3α Inhibition in Drug-Resistant CML Cells Promotes Susceptibility to NK Cell-Mediated Lysis in an NKG2D- and NKp30-Dependent Manner.

Simple SummaryGlycogen synthase kinase-3 (GSK-3) is a serine/threonine protein kinase that has gained considerable interest as a therapeutic target for cancer due to its key involvement in growth arrest and apoptosis of tumor cells. Moreover, GSK-3, especially GSK-3β, limits the activation of NK cells, key innate effectors in cancer immunosurveillance, triggered by diverse activating receptors. However, the role of GSK-3 in the regulation of activating ligands on target cells that confer susceptibility to NK cells remains unclear and is the aim of this study. Here, we provide evidence that GSK-3α primarily restrains the expression of ligands for activating receptors such as NKG2D, NKp30 but not DNAM-1, thereby reducing target susceptibility to NK cells. Thus, our results suggest a distinct role of GSK-3 isoforms in target cells vs NK cells for regulating NK cell reactivity and GSK-3α inhibition as a relevant strategy to enhance target susceptibility to NK cells.Natural killer (NK) cells are innate cytotoxic lymphocytes that provide early protection against cancer. NK cell cytotoxicity against cancer cells is triggered by multiple activating receptors that recognize specific ligands expressed on target cells. We previously demonstrated that glycogen synthase kinase (GSK)-3β, but not GSK-3α, is a negative regulator of NK cell functions via diverse activating receptors, including NKG2D and NKp30. However, the role of GSK-3 isoforms in the regulation of specific ligands on target cells is poorly understood, which remains a challenge limiting GSK-3 targeting for NK cell-based therapy. Here, we demonstrate that GSK-3α rather than GSK-3β is the primary isoform restraining the expression of NKG2D ligands, particularly ULBP2/5/6, on tumor cells, thereby regulating their susceptibility to NK cells. GSK-3α also regulated the expression of the NKp30 ligand B7-H6, but not the DNAM-1 ligands PVR or nectin-2. This regulation occurred independently of BCR-ABL1 mutation that confers tyrosine kinase inhibitor (TKI) resistance. Mechanistically, an increase in PI3K/Akt signaling in concert with c-Myc was required for ligand upregulation in response to GSK-3α inhibition. Importantly, GSK-3α inhibition improved cancer surveillance by human NK cells in vivo. Collectively, our results highlight the distinct role of GSK-3 isoforms in the regulation of NK cell reactivity against target cells and suggest that GSK-3α modulation could be used to enhance tumor cell susceptibility to NK cells in an NKG2D- and NKp30-dependent manner.

IDO1‐mediated Trp‐kynurenine‐AhR signal activation induces stemness and tumor dormancy in oral squamous cell carcinomas

AbstractThe non‐proliferative residual tumor cells in cancer therapeutics are considered tumor‐repopulating cells (TRCs) and a major issue for tumor recurrences and distant metastases. TRCs are stem cell‐like cancer cells repopulating tumors and associating with immune‐mediated tumor dormancy. Cell cycle arrest is also coupled to a tumor‐initiating or pluripotent capacity. INF‐γ, a cytokine with an anti‐tumor effect, also acts as an inhibitory effect on the cancer immune response via the induction of PD‐L1 on the surface of cancer cells. The anti‐tumor immune response may shift TRCs from proliferation to dormancy by a specific mechanism. Indoleamine 2, 3‐dioxygenase 1 (IDO1) is a metabolic enzyme to produce kynurenine (KYN) from tryptophan (Trp) and is expressed in cancer cells and dendritic cells in the immune system. IDO1 plays an important role for cancer cells to evade the attack from the activated CTLs. Recently, the signaling from the interaction between KYN and aryl hydrocarbon receptor (AhR), a dioxin receptor, has been reported to induce cancer cell dormancy. However, it is currently unclear what is the immune mechanism for the entry of tumor into dormancy and how stemness is coupled to the tumor cell arrest. In this study, we revealed that IDO1 induced by IFN‐γ activated Trp‐KYN‐AhR signaling and induced stemness in OSCC cells contributing to the entry of tumor into dormancy. In this mechanism, it was suggested that STAT1 was a key regulator between tumor differentiation and tumor dormancy. The regulation of IDO1‐mediated Trp‐KYN‐AhR signal activation could provide a new strategy for the cancer treatment.

Discovery of 3,5-dimethylisoxazole derivatives as novel, potent inhibitors for bromodomain and extraterminal domain (BET) family

Bromodomain and extra-terminal (BET) is a promising therapeutic target for various hematologic cancers. We used the BRD4 inhibitor compound 13 as a lead compound to develop a variety of compounds, and we introduced diverse groups into the position of the compound 13 orienting toward the ZA channel. A series of compounds (14–23, 38–41, 43, 47–49) bearing triazolopyridazine motif exhibited remarkable BRD4 protein inhibitory activities. Among them, compound 39 inhibited BRD4(BD1) protein with an IC50 of 0.003 μM was superior to lead compound 13. Meanwhile, compound 39 possess activity, IC50 = 2.1 μM, in antiproliferation activity against U266 cancer cells. On the other hand, compound 39 could arrest tumor cells into the G0/G1 phase and induce apoptosis, which was consistent with its results in inhibiting cell proliferation. Biological and biochemical data suggest that BRD4 protein might be a therapeutic target and that compound 39 is an excellent lead compound for further development.

Research progress on anti-tumor effect of Chinese dragon's blood

As a traditional Chinese medicine, Chinese dragon's blood has multiple effects, such as activating blood to remove blood stasis, softening and dispelling stagnation, astringent and hemostasis, clearing swelling and relieving pain, regulating menstruation and rectifying the blood, so it is called &quot;an effective medicine of promoting blood circulation&quot;. It has been widely used clinically to treat a variety of diseases. With the further research on Chinese dragon's blood, its anti-tumor medicinal value is gradually emerging. Modern pharmacological studies have shown that Chinese dragon's blood exerts anti-tumor effects mainly by inhibiting cell proliferation, inducing apoptosis, inducing DNA damage and cell cycle arrest, inducing senescence and autophagy of tumor cells, inhibiting metastasis and angiogenesis, as well as reversing multidrug resistance. This article focuses on the research progress on anti-tumor effects of Chinese dragon's blood extract and its chemical components, with a view to provide new references for the in-depth research and reasonable utilization of Chinese dragon's blood.

Design and Synthesis of Novel N‐(2‐aminophenyl)benzamide Derivatives as Histone Deacetylase Inhibitors and Their Antitumor Activity Study

Histone deacetylases (HDACs) are promising therapeutic targets for cancer therapy because inhibition of HDACs triggers growth arrest or apoptosis of tumor cells. In the present study, a new series of fluorinated N‐(2‐aminophenyl)benzamide derivatives were synthesized to investigate potential inhibition of HDACs and associated anticancer activity. Among the synthesized derivatives, compound 24a showed potent inhibitory activity of HDACs and higher antitumor efficacy in human cancer cell lines (HCT‐116, MCF‐7, and A549) compared with SAHA. Moreover, animal studies demonstrated that compound 24a showed potent in vivo antitumor efficacy in an HCT‐116 colon cancer xenograft mouse model.

Visualization of Radiation-Induced Cell Cycle Kinetics with a Fluorescent Ubiquitination-Based Cell Cycle Indicator (Fucci).

Among the methods for detecting cell cycle kinetics in tumor cells, fluorescent ubiquitination-based cell cycle indicator (Fucci) is innovative because it allows observation in live cells without losing spatiotemporal information. We succeeded in using the Fucci system to visualize radiation-induced G2 arrest in tumor cells with deficient p53 function. Here we describe protocols for establishing Fucci-expressing cell lines and analyzing radiation-induced G2 arrest kinetics in three different models: monolayer cell cultures, spheroids, and xenografted solid tumors in mice.

Therapeutic effects of dihydroartemisinin in multiple stages of colitis-associated colorectal cancer

Colitis-associated colorectal cancer (CAC) develops from chronic intestinal inflammation. Dihydroartemisinin (DHA) is an antimalarial drug exhibiting anti-inflammatory and anti-tumor effects. Nonetheless, the therapeutic effects of DHA on CAC remain unestablished.Methods: Mice were challenged with azoxymethane (AOM) and dextran sulfate sodium (DSS) to establish CAC models. DHA was administered via oral gavage in different stages of CAC models. Colon and tumor tissues were obtained from the AOM/DSS models to investigate inflammatory responses and tumor development. Inflammatory cytokines in the murine models were detected through qRT-PCR and ELISA. Toll-like receptor 4 (TLR4) signaling-related proteins were detected by western blot. Macrophage infiltration was measured using immunostaining analysis, and apoptosis in the colon cancer cells was detected by flow cytometry and western blot.Results: DHA inhibited inflammatory responses in the early stage of the AOM/DSS model and subsequent tumor formation. In the early stage, DHA reversed macrophage infiltration in colon mucosa and decreased the expression of pro-inflammatory cytokines. DHA inhibited the activation of macrophage by suppressing the TLR4 signal pathway. In the late stage of CAC, DHA inhibited tumor growth by enhancing cell cycle arrest and apoptosis in tumor cells. Administration of DHA during the whole period of the AOM/DSS model generated an addictive effect based on the inhibition of inflammation and tumor growth, thereby improving the therapeutic effect of DHA on CAC.Conclusion: Our study indicated that DHA could be a potent agent in managing the initiation and development of CAC without obvious side effects, warranting further clinical translation of DHA for CAC treatment.

Injectable Hyaluronic Acid Hydrogel for the Co-Delivery of Gemcitabine Nanoparticles and Cisplatin for Malignant Ascites Therapy.

Malignant ascites indicate the presence of malignant cells in the peritoneal cavity that lower patient survival and reduce quality of life. Current chemotherapy regimens suffer from the dilution of ascites and rapid metabolism limiting their therapeutic efficacy. The storage and sustained release of drugs at the tumor site represents a promising strategy to improve drug efficacy. The aim of this study was to develop injectable hyaluronic acid hydrogel containing polymeric gemcitabine nanoparticles and cisplatin for the local treatment of malignant ascites through a dual sustained drug release pattern. Cell uptake assays showed that the drug-loaded nanoparticles readily entered tumor cells. Apoptosis and cell cycle analysis showed that the hydrogel system could enhance tumor cell apoptosis and arrest more cells in the G1 phase. In vivo experiments indicated that mice treated with the drug-loaded hydrogels manifested the most significant efficacy in ascites volume, tumor nodules, body weight, abdominal circumference, and survival. The expression of Ki-67 and CD31 also significantly decreased compared with other groups, indicative of anti-tumor activity. In addition, intraperitoneal administration of the hydrogel system led to no significant damage to vital organs. These findings confirm the clinical potential of the drug-loaded hydrogel system for the treatment of malignant ascites.

Abstract 4808: ONC201 decreases protein chaperone ClpX to unleash mitochondrial protease ClpP activity, intregrated stress response and tumor cell death

Abstract Brain tumors are one of the most lethal cancers in children and young adults. We previously reported that first-in-class small-molecule imipridone ONC201 can antagonize dopamine receptor D2 (DRD2), inactivate ERK/AKT, induce the integrated stress response (ISR), upregulate pro-apoptotic TRAIL receptor DR5, deplete cancer stem cells, and induce growth arrest or cell death in tumor cells. ONC201 crosses the blood-brain barrier and has induced durable tumor regressions in adult and pediatric H3K27M-mutant glioma patients. We hypothesized that ONC201 may synergize with radiotherapy and temozolomide in brain tumors. Glioblastoma (GBM: SNB19, T98G and U251), diffuse intrinsic pontine glioma (DIPG: SU-DIPG-IV and SU-DIPG-36) and atypical teratoid rhabdoid tumor (ATRT: BT-12, BT-16) cell lines were tested using cell viability or colony formation assays with ONC201 up to 20 μM alone or in combination with radiotherapy up to 8 Gy and temozolomide up to 100 μM. We observed synergy between ONC201 and radiation and temozolomide by multiple assays with the best combination index of 0.31 under the treatment of 0.625 μM ONC201, 25 μM TMZ and 4 Gy irradiation in cell viability assay. We observed induction of PKA substrate phosphorylation as a marker of DRD2 antagonism, induction of ATF4 as a marker of ISR activation, and multiple markers of cell death in treated brain tumor cells. Mitochondrial dysfunction induced by ONC201 was greatly reflected in reduction of maximal cell respiration in brain tumor cell lines. ClpXP is a proteolytic machine in mitochondria comprising of the protein chaperone ClpX and protease ClpP, a recently described binding target of ONC201. We have observed that ONC201 induced cytotoxicity depends on ClpP and knockdown of ClpP strongly protects multiple human cancer cell lines from ONC201-mediated (but not other drugs, e.g. temozolomide) cytotoxicity. The ClpX protein level decreased dramatically upon ONC201 treatment. We are exploring the potential interplay between ClpP, dopamine receptors, the ISR and TRAIL signaling pathways after single agent or combinatorial treatments. Our data suggests that ONC201 may be combined synergistically with temozolomide or radiation to address gliomas, along with potential pharmacodynamic biomarkers. The results implicate ClpX and ClpP in downstream cell death induction following ONC201 treatment of brain tumor cells. Citation Format: Lanlan Zhou, Howard P. Safran, Michael J. Glantz, Wafik S. El-Deiry. ONC201 decreases protein chaperone ClpX to unleash mitochondrial protease ClpP activity, intregrated stress response and tumor cell death [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4808.

Dolutegravir derivative inhibits proliferation and induces apoptosis of non-small cell lung cancer cells via calcium signaling pathway

Non-small cell lung cancer (NSCLC) is the most prevalent type of lung cancer. However, there has been little improvement in its cure rate in the last 30 years, due to its intricate heterogeneity and drug resistance. Accumulating evidences have demonstrated that dysregulation of calcium (Ca2+) homeostasis contributes to oncogenesis and promotes tumor development. Inhibitors of Ca2+ channels/transporters to restore intracellular Ca2+ level were found to arrest tumor cell division, induce apoptosis, and suppress tumor growth both in vitro and in vivo. Dolutegravir (DTG), which is a first-line drug for Acquired Immune Deficiency Syndrome (AIDs) treatment, has been shown to increase intracellular Ca2+ levels and Reactive oxygen species (ROS) levels in human erythrocytes, leading to suicidal erythrocyte death or eryptosis. To explore the potential of DTG as an antitumor agent, we have designed and synthesized a panel of compounds based on the principle of biologically active substructure splicing of DTG. Our data demonstrated that 7-methoxy-4-methyl-6,8-dioxo-N-(3-(1-(2-(trifluoromethyl)phenyl)-1H-1,2,3-triazol-4-yl)phenyl)-3,4,6,8,12,12a-hexahydro-2H-pyrido[1′,2′:4,5]pyrazino[2,1-b][1,3]oxazine-9-carboxamide (DTHP), a novel derivative of DTG, strongly inhibited the colony-forming ability and proliferation of NSCLC cells, but displayed no cytotoxicity to normal lung cells. DTHP treatment also induced apoptosis and upregulate intracellular Ca2+ level in NSCLC cells significantly. Inhibiting Ca2+ signaling alleviated DTHP-induced apoptosis, suggesting the perturbation of intracellular Ca2+ is responsible for DTHP-induced apoptosis. We further discovered that DTHP activates AMPK signaling pathway through binding to SERCA, a Ca2+-ATPase. On the other hand, DTHP treatment promoted mitochondrial ROS production, causing mitochondrial dysfunction and cell death. Finally, DTHP effectively inhibited tumor growth in the mouse xenograft model of lung cancer with low toxicity to normal organs. Taken together, our work identified DTHP as a superior antitumor agent, which will provide a novel strategy for the treatment of NSCLC with potential clinical application.

Biology of Glioblastoma Multiforme-Exploration of Mitotic Catastrophe as a Potential Treatment Modality.

Glioblastoma multiforme (GBM) represents approximately 60% of all brain tumors in adults. This malignancy shows a high biological and genetic heterogeneity associated with exceptional aggressiveness, leading to a poor survival of patients. This review provides a summary of the basic biology of GBM cells with emphasis on cell cycle and cytoskeletal apparatus of these cells, in particular microtubules. Their involvement in the important oncosuppressive process called mitotic catastrophe will next be discussed along with select examples of microtubule-targeting agents, which are currently explored in this respect such as benzimidazole carbamate compounds. Select microtubule-targeting agents, in particular benzimidazole carbamates, induce G2/M cell cycle arrest and mitotic catastrophe in tumor cells including GBM, resulting in phenotypically variable cell fates such as mitotic death or mitotic slippage with subsequent cell demise or permanent arrest leading to senescence. Their effect is coupled with low toxicity in normal cells and not developed chemoresistance. Given the lack of efficient cytostatics or modern molecular target-specific compounds in the treatment of GBM, drugs inducing mitotic catastrophe might offer a new, efficient alternative to the existing clinical management of this at present incurable malignancy.