A novel agent exerts antitumor activity in breast cancer cells by targeting mitochondrial complex II.
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ABSTRACT:
SUBMITTER: Wang L
PROVIDER: S-EPMC5077996 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Mitochondria play a pivotal role in cancer bioenergetics and are considered a potential target for anticancer therapy. Considering the limited efficacy and toxicity of currently available mitochondria-targeting agents, it is necessary to develop effective mitochondria-targeting anticancer drugs. By screening a large chemical library consisting of natural products with diverse chemical entities, we identified gracillin, a steroidal saponin, as a mitochondria-targeting antitumor drug. Gracillin displayed broad-spectrum inhibitory effects on the viability of a large panel of human cancer cell lines, including those carrying acquired resistance to chemotherapy or EGFR-targeting drugs, by inducing apoptosis. We show that gracillin attenuates mitochondria-mediated cellular bioenergetics by suppressing ATP synthesis and by producing reactive oxygen species (ROS). Mechanistically, gracillin disrupts complex II (CII) function by abrogating succinate dehydrogenase (SDH) activity without affecting the succinate:ubiquinone reductase. The gracillin-induced cell death was potentiated by 3-nitropropionic acid (3-NPA) or thenoyltrifluoroacetone (TTFA), which inhibit CII by binding to the active site of SDHA or to the ubiquinone-binding site, respectively. Finally, we show that gracillin effectively suppressed the mutant-Kras-driven lung tumorigenesis and the growth of xenograft tumors derived from cell lines or patient tissues. Gracillin displayed no obvious pathophysiological features in mice. Collectively, gracillin has potential as a CII-targeting antitumor drug.
| S-EPMC6813327 | biostudies-literature
Project description:Currently, targeting the autophagic pathway is regarded as a promising new strategy for cancer drug discovery. Here, we screened the North China Pharmaceutical Group Corporation's pure compound library of microbial origin using GFP-LC3B-SKOV3 cells and identified elaiophylin as a novel autophagy inhibitor. Elaiophylin promotes autophagosome accumulation but blocks autophagic flux by attenuating lysosomal cathepsin activity, resulting in the accumulation of SQSTM1/p62 in various cell lines. Moreover, elaiophylin destabilizes lysosomes as indicated by LysoTracker Red staining and CTSB/cathepsin B and CTSD/ cathepsin D release from lysosomes into the cytoplasm. Elaiophylin eventually decreases cell viability, especially in combination with cisplatin or under hypoxic conditions. Furthermore, administration of a lower dose (2 mg/kg) of elaiophylin as a single agent achieves a significant antitumor effect without toxicity in an orthotopic ovarian cancer model with metastasis; however, high doses (8 mg/kg) of elaiophylin lead to dysfunction of Paneth cells, which resembles the intestinal phenotype of ATG16L1-deficient mice. Together, these results provide a safe therapeutic window for potential clinical applications of this compound. Our results demonstrate, for the first time, that elaiophylin is a novel autophagy inhibitor, with significant antitumor efficacy as a single agent or in combination in human ovarian cancer cells, establishing the potential treatment of ovarian cancer by this compound.
| S-EPMC4824600 | biostudies-literature
Project description:PurposeOverall, ~65% of patients diagnosed with advanced ovarian cancer (OC) will relapse after primary surgery and adjuvant first-line platinum- and taxane-based chemotherapy. Significant improvements in the treatment of OC are expected from the development of novel compounds having combined cytotoxic and antiangiogenic properties that make them effective on refractory tumors.MethodsPermeability of NOV202 was determined with Caco-2 monolayer assay. The compound's pharmacokinetic profile and plasma:brain distribution were assessed in male C57Bl/6 mice. The compound's impacts on tubulin, microtubules and cell cycle were investigated by using in vitro tubulin polymerization assay, cell-based immunofluorescence and live cell microscopy. The IC50 concentrations of NOV202 were assessed in a panel of eight cancer cell lines. Impact of the compound on vascular tube formation was determined using the StemKit and Chick chorioallantoic membrane assays. The in vivo efficacy of the compound was analyzed with an OC xenograft mouse model.ResultsNOV202 was found to suppress cancer cell proliferation at low nanomolar concentrations (IC50 2.3-12.0 nM) and showed equal efficacy between OC cell line A2780 (IC50 2.4 nM) and its multidrug-resistant subline A2780/Adr (IC50 2.3 nM). Mechanistically, NOV202 targeted tubulin polymerization in vitro in a dose-dependent manner and in cells induced an M phase arrest. In vivo, NOV202 caused a dose-dependent reduction of tumor mass in an A2780 xenograft model, which at the highest dose (40 mg/kg) was comparable to the effect of paclitaxel (24 mg/kg). Interestingly, NOV202 exhibited vascular disrupting properties that were similar to the effects of Combretastatin A4.ConclusionNOV202 is a novel tubulin and vascular targeting agent that shows strong anticancer efficacy in cells and OC xenograft models. The finding that the compound induced significantly more cell death in Pgp/MDR1 overexpressing OC cells compared to vincristine and paclitaxel warrants further development of the compound as a new therapy for OC patients with treatment refractory tumors and/or relapsing disease.
| S-EPMC5417661 | biostudies-literature
Project description:Pheochromocytomas (PCC) are mostly benign tumors, amenable to complete surgical resection. However, 10–17% of cases can become malignant, and once metastasized, there is no curative treatment for this disease. Given the need to identify effective therapeutic approaches for PCC, we evaluated the antitumor potential of the dual PI3K/mTOR inhibitor BEZ235 against these tumors. We employed an in vivo model of endogenous PCCs (MENX mutant rats), which closely recapitulate the human tumors. Mutant rats with PCCs were treated with 2 doses of BEZ235 (20 and 30 mg/kg), or with placebo, for 2 weeks. Treatment with BEZ235 induced cytostatic and cytotoxic effects on rat PCCs, which could be appreciated by both staining the tumors ex vivo with appropriate markers, and non-invasively by functional imaging (diffusion weighted-DW-MRI) in vivo. Transcriptomic analyses of tumors from rats treated with BEZ235 or placebo identified potential mediators of therapy response. Slc6a2, encoding the norepinephrine transporter (NET), was downregulated in a dose-dependent manner by BEZ235 in rat PCCs. Moreover, BEZ235 reduced Slc6a2/NET expression also in PCC cell lines (PC12, MPC, MTT). Studies of a BEZ235-resistant derivative of the MPC cell line (MPCR) confirmed that the reduction of NET expression associates with the response to the drug. Reduction of NET expression following BEZ235 treatment in vivo could be monitored by Positron Emission Tomography (PET) using a tracer targeting NET. Altogether, we demonstrate the efficacy of BEZ235 against PCC in vivo, and show that functional imaging can be employed to monitor the response of PCC to PI3K/mTOR inhibition therapy.
2016-11-03 | GSE83401 | GEO
Project description:BackgroundBreast cancer is one of the leading causes of cancer-related morbidities. The present study aimed to evaluate the efficacy of bithiophene-fluorobenzamidine (BFB) against breast cancer induced by 7,12-dimethylbenz(a)anthracene (DMBA) in female Swiss mice and reveal the underlining mechanisms.MethodsThe mice were randomly divided into five groups; control, BFB-treated group, DMBA-treated group, and the last two groups received DMBA then tamoxifen or BFB.ResultsBFB reduced the tumor incidence by ~ 88% versus 30% after TAM. DMBA significantly increased the expression of CDK1 and HER2 and reduced the expression of p53, p21 (CDKN1A), ESR-α, and CAS3. BFB caused significant down-regulation of CDK1 and HER2 and upregulation of p53, p21, ESR-α, and CAS3. In the DMBA-treated mice, cancerous cells metastasized to several organs. This was prevented by the administration of BFB. The antimetastatic and proapoptotic activities were confirmed in MCF7 cells in vitro by the wound healing and annexin V assays, respectively. Kaplan-Meier analysis showed that the BFB increased survival. In the DMBA group, tumors showed invasive carcinoma of grade III with central necrosis, polymorphism, mitotic activity, and numerous newly formed ductules, and colloidal mucinous secretions within adenoid cysts. BFB administration restored the normal structure of the mammary glands.ConclusionTaken together, BFB has antitumor, pro-apoptotic, and anti-metastatic activities against breast cancer in mice and therefore, it merits further investigations.
| S-EPMC9478011 | biostudies-literature
Project description:The human prolyl isomerase PIN1, best known for its association with carcinogenesis, has recently been indicated in the disease of pancreatic ductal adenocarcinoma (PDAC). However, the functions of PIN1 and the feasibility of targeting PIN1 in PDAC remain elusive. For this purpose, we examined the expression of PIN1 in cancer, related paracarcinoma and metastatic cancer tissues by immunohistochemistry and analyzed the associations with the pathogenesis of PDAC in 173 patients. The functional roles of PIN1 in PDAC were explored in vitro and in vivo using both genetic and chemical PIN1 inhibition. We showed that PIN1 was upregulated in pancreatic cancer and metastatic tissues. High PIN1 expression is significantly association with poor clinicopathological features and shorter overall survival and disease-free survival. Further stratified analysis showed that PIN1 phenotypes refined prognostication in PDAC. Inhibition of PIN1 expression with RNA interference or with all trans retinoic acid decreased not only the growth but also the migration and invasion of PDAC cells through regulating the key molecules of multiple cancer-driving pathways, simultaneously resulting in cell cycle arrest and mesenchymal-epithelial transition in vitro. Furthermore, genetic and chemical PIN1 ablation showed dramatic inhibition of the tumorigenesis and metastatic spread and then reduced the tumor burden in vivo. We provided further evidence for the use of PIN1 as a promising therapeutic target in PDAC. Genetic and chemical PIN1 ablation exerted potent antitumor effects through blocking multiple cancer-driving pathways in PDAC. More potent and specific PIN1 targeted inhibitors could be exploited to treat this aggressive cancer.
| S-EPMC6676117 | biostudies-literature
Project description:The camptothecin derivatives topoisomerase I (TOP1) inhibitors, irinotecan and topotecan, are FDA approved for the treatment of colorectal, ovarian, lung and breast cancers. Because of the chemical instability of camptothecins, short plasma half-life, drug efflux by the multidrug-resistance ABC transporters, and the severe diarrhea produced by irinotecan, indenoisoquinoline TOP1 inhibitors (LMP400, LMP776, and LMP744), which overcome these limitations, have been developed and are in clinical development. Further modifications of the indenoisoquinolines led to the fluoroindenoisoquinolines, one of which, LMP517, is the focus of this study. LMP517 showed better antitumor activity than its parent compound LMP744 against H82 (small cell lung cancer) xenografts. Genetic analyses in DT40 cells showed a dual TOP1 and TOP2 signature with selectivity of LMP517 for DNA repair-deficient tyrosyl DNA phosphodiesterase 2 (TDP2)- and Ku70-knockout cells. RADAR assays revealed that LMP517, and to a lesser extent LMP744, induce TOP2 cleavage complexes (TOP2cc) in addition to TOP1ccs. Histone γH2AX detection showed that, unlike classical TOP1 inhibitors, LMP517 targets cells independently of their position in the cell cycle. Our study establishes LMP517 as a dual TOP1 and TOP2 inhibitor with therapeutic potential.
| S-EPMC7415565 | biostudies-literature
Project description:Mitochondrial complex II (CII) has been recently identified as a novel target for anti-cancer drugs. Mitochondrially targeted vitamin E succinate (MitoVES) is modified so that it is preferentially localized to mitochondria, greatly enhancing its pro-apoptotic and anti-cancer activity. Using genetically manipulated cells, MitoVES caused apoptosis and generation of reactive oxygen species (ROS) in CII-proficient malignant cells but not their CII-dysfunctional counterparts. MitoVES inhibited the succinate dehydrogenase (SDH) activity of CII with IC(50) of 80 ?M, whereas the electron transfer from CII to CIII was inhibited with IC(50) of 1.5 ?M. The agent had no effect either on the enzymatic activity of CI or on electron transfer from CI to CIII. Over 24 h, MitoVES caused stabilization of the oxygen-dependent destruction domain of HIF1? fused to GFP, indicating promotion of the state of pseudohypoxia. Molecular modeling predicted the succinyl group anchored into the proximal CII ubiquinone (UbQ)-binding site and successively reduced interaction energies for serially shorter phytyl chain homologs of MitoVES correlated with their lower effects on apoptosis induction, ROS generation, and SDH activity. Mutation of the UbQ-binding Ser(68) within the proximal site of the CII SDHC subunit (S68A or S68L) suppressed both ROS generation and apoptosis induction by MitoVES. In vivo studies indicated that MitoVES also acts by causing pseudohypoxia in the context of tumor suppression. We propose that mitochondrial targeting of VES with an 11-carbon chain localizes the agent into an ideal position across the interface of the mitochondrial inner membrane and matrix, optimizing its biological effects as an anti-cancer drug.
| S-EPMC3030374 | biostudies-literature
Project description:BackgroundBispecific antibody has garnered considerable attention in the recent years due to its impressive preliminary efficacy in hematological malignancies. For solid tumors, however, the main hindrance is the suppressive tumor microenvironment, which effectively impedes the activation of infiltrating T cells. Herein, we designed a bispecific antibody AP203 with high binding affinity to PD-L1 and CD137 and assessed its safety and anti-tumor efficacy, as well as explored the mechanism of action.MethodsThe optimal antibody binders against PD-L1 and CD137 were screened from the OmniMab phagemid library. The binding affinity of the constructed AP203 were evaluated using enzyme-linked immunosorbent assay (ELISA) and biolayer interferometry (BLI). T-cell stimulatory capacity was assessed using the allogeneic mixed lymphocyte reaction (MLR), antigen-specific recall response, and coculture with PD-L1-expressing cells. In vivo antitumor efficacy was evaluated using two models of tumor-xenografted humanized mice with profiling of tumor infiltrating lymphocytes (TILs). The possible toxicity of AP203 was examined using in vitro cytokine release assay by human PBMCs.ResultsAP203, which simultaneously targeted PD-L1 and costimulatory CD137, elicit superior agonistic effects over parental antibodies alone or in combination in terms of T cell activation, enhanced memory recall responses, and overcoming Treg-mediated immunosuppression (P < 0.05). The agonistic activity of AP203 was further demonstrated PD-L1-dependent by coculturing T cells with PD-L1-expressing cells. In vivo animal studies using immunodeficient or immunocompetent mice both showed a dose-related antitumor efficacy superior to parental antibodies in combination (P < 0.05). Correspondingly, AP203 significantly increased tumor infiltrating CD8 + T cells, while decreased CD4 + T cells, as well as Treg cells (P < 0.05), resulting in a dose-dependent increase in the CD8 + /CD4 + ratio. Moreover, either soluble or immobilized AP203 did not induce the production of inflammatory cytokines by human PBMCs.ConclusionsAP203 exerts potent antitumor activity not only by blocking PD-1/PD-L1 inhibitory signaling, but also by activating CD137 costimulatory signaling in effector T cells that consequently counteracts Treg-mediated immunosuppression. Based on promising preclinical results, AP203 should be a suitable candidate for clinical treatment of solid tumors.
| S-EPMC10210478 | biostudies-literature
Project description:Opioids are a potential adjuvant treatment for certain cancers; while they are primarily used to relieve chronic pain, these drugs may also affect cancer progression and recurrence. Dezocine is one opioid commonly used in China, but its effects on cancer cells are unknown. Here, we demonstrated the inhibitory effect of dezocine on triple-negative breast cancer (TNBC) cells, and determined the underlying molecular mechanism. We found that dezocine suppressed cell proliferation, migration and invasion, and induced apoptosis in TNBC cells. Xenograft models demonstrated the inhibitory effects of dezocine treatment on TNBC tumor growth in vivo. The anticancer effects of dezocine were independent of opioid receptors, which are not highly expressed by normal breast or breast cancer tissues. A pull-down assay and LC-MS/MS analysis indicated that dezocine directly targets NAMPT: computer modeling verified that the free energy of dezocine kinetically bound into the pocket of NAMPT was -17.4 kcal/mol. Consequently, dezocine treatment inhibited NAMPT enzyme activity, resulting in cellular NAD abolishment. We confirmed the dezocine-induced inhibition of cell proliferation by both NAMPT knockdown and upon treatment with the inhibitor FK866. Our results suggest that both dezocine and NAMPT might represent novel therapeutic targets for TNBC.
| S-EPMC8072669 | biostudies-literature