scholarly journals Akt Inhibition Improves the Efficacy of Cabazitaxel Nanomedicine in Preclinical Taxane-Resistant Cancer Models

2020 ◽  
Author(s):  
Tongyu Li ◽  
Linlin Shi ◽  
Jianqin Wan ◽  
Xiaoxiao Hu ◽  
Wanzhi Chen ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Western Blotting ◽  
Combined Treatment ◽  
Xenograft Model ◽  
Akt Inhibitor ◽  
Defense Proteins ◽  
Western Blotting Assay ◽  
Resistant Cells

Abstract Background: Drug resistance continues to be a major clinical challenge in achieving cures in cancer patients. Cabazitaxel has shown the ability to surmount drug resistance through bypassing the transporter-mediated drug expulsion; however, the substantially high toxicity in patients hampered its clinical application. In addition, upregulation of certain self-defense proteins (e.g, Akt) was reportedly involved in drug resistance, which may further compromise the activity of cabazitaxel. We have previously developed several prodrug-based strategies to deliver nanoparticles encapsulating cabazitaxel derivatives in tumors with enhanced efficacy and improved in vivo tolerability. Therefore, we hypothesized that combing cabazitaxel nanotherapeutics with a pan-Akt inhibitor MK-2206 would synergistically eliminate the resistant cancers with reduced systemic toxicity.Methods: Activation of Akt in resistant cancers upon cabazitaxel treatment was determined by western blotting assay. The effect of combing MK-2206 with cabazitaxel on cell viability was evaluated by CCK-8 assay. To improve the in vivo biocompatibility, the delivery of potent cabazitaxel was feasibly achieved via the integration of oligolactide-conjugated cabazitaxel into the PEG-b-PLA matrix. Both the synergism and safety of cabazitaxel nanomedicine-based combination were evaluated through a series of in vitro and in vivo experiments, including Western blotting assay, CCK-8 assay, EdU assay, flow cytometry, migration assay, transwell assay, MTD study, myelosuppression study, nude mouse xenograft, and immunostaining analyses. Results: We found that resistant cells adapted to activate Akt signaling upon cabazitaxel treatment, which potentially discounts the efficacy of cabazitaxel. The addition of MK-2206 reversed this situation and potentiated the activity of cabazitaxel nanomedicine against resistant cells. Mechanistically, suppression of the Akt pathway increased the microtubule-stabilizing effect of cabazitaxel. Their collaboration was demonstrated to maximize the efficacy in a xenograft model bearing paclitaxel-resistant tumors. In particular, the nanoformulation substantially improved drug tolerability in animals, and combined treatment with MK-2206 was proven to be safe for synergistic cancer therapy. Conclusion: The preclinical studies demonstrate the therapeutic efficacy of our binary system consisting of a better-tolerated nanotherapy and a specific pathway modulator against resistant cells, thereby highlighting the potential applications for the clinical treatment of patients with multidrug-resistant malignancies.

CARD8/BCL-2 cascade in early adaptive drug resistant tumor escape against targeted inhibitors in NSCLC.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e22032-e22032
Author(s):  
Rakesh K. Bagai ◽  
Wei Zhang ◽  
Patrick Leahy ◽  
Lihong Yin ◽  
Patrick C. Ma
Keyword(s):  
Lung Cancer ◽  
Drug Resistance ◽  
Expression Analysis ◽  
Xenograft Model ◽  
Tumor Escape ◽  
Apoptosis Pathway ◽  
Egfr Tki ◽  
Resistant Cells

e22032 Background: Lung cancer targeted therapy is largely limited by inevitable recurrent resistant disease after initial response to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), typically accompanied with divergent late acquired resistance mechanisms. We now focused on studying the emergence of early adaptive resistance to uncover attractive therapeutic targets to overcome drug resistance. Methods: HCC827 cells were treated with EGFR-TKI (0-9 days) with apoptosis pathway-specific QPCR array and TLVM analysis performed. MTS and crystal violet assays were performed. Western blot analysis was performed to examine prosurvival signaling developed against erlotinib, alone or in combination with MET inhibitor SU11274. IHC was performed on lung cancer tumor microarray (TMA) using BCL-2 and caspase-recruitment domain-containing protein 8 (CARD8) antibodies and graded (4 tier scoring system). NSCLC cell lines and murine xenograft models (HCC827, H1975) were developed for resistance biomarkers expression analysis in pre-/post-TKI treatment using anti-human CARD8, p-STAT3 and BCL-2 antibodies. Results: We characterized the emergence of early resistant lung cancer cells in escape against targeted TKIs with 100-fold higher IC50 in adaptive drug resistance. The resistant cells that evaded EGFR-TKI based targeted inhibition exhibited MET-independent induction of CARD8 and STAT3/BCL-2 mitochondrial prosurvival signaling in cellular quiescence, and inhibited cytoskeletal functions. Expression analysis studies demonstrated common tumor-associated expression of CARD8 but relatively low BCL-2 level in NSCLC. In vitro cell line studies suggest that CARD8 induction was preceded by a resurgence of STAT3 activation. In vivo xenograft model (HCC827/erlotinib; H1975/erlotinib+ SU11274) also verified upregulated CARD8/BCL-2 activation within early resistant cells. Conclusions: Resistant tumor cells that evaded EGFR inhibitors, alone or in combination with MET inhibitors, exhibited increased expression of CARD8-STAT3/BCL-2 prosurvival signaling cascade. Further studies to define the mechanism of CARD8 in promoting adaptive tumor drug resistance would be warranted.

scholarly journals Silencing VEGF enhances the radiosensitivity of the radioresistant human nasopharyngeal carcinoma cell line CNE-2R by inhibiting autophagy through the activation of mTOR pathway

2020 ◽  
Author(s):  
Li Chen ◽  
Guoxiang Lin ◽  
Kaihua Chen ◽  
Fangzhu Wan ◽  
Yongchu Sun ◽  
...  
Keyword(s):  
Dna Damage ◽  
Nasopharyngeal Carcinoma ◽  
Cell Line ◽  
Western Blotting ◽  
Xenograft Model ◽  
Mtor Pathway ◽  
Angiogenic Factor ◽  
Cell Counting

Abstract Background: Vascular endothelial growth factor (VEGF) is an important pro-angiogenic factor. VEGF was reported to promote the occurrence of autophagy, which enhanced to the radioresistance of tumors. The purpose of our study was to investigate the influence of VEGF silencing on the radiosensitivity of nasopharyngeal carcinoma radioresistant cell line CNE-2R and the underlying mechanisms.Methods: The radiosensitivity of CNE-2R cells after silencing VEGF was detected by cell counting kit 8 (CCK-8) and clonogenic assay, cell cycle and apoptosis was subjected to flow cytometry. DNA damage and autophagy were observed by immunofluorescence and western blotting. The interaction between VEGF and mTOR was confirmed by western blotting and co-immunoprecipitation analysis. In vivo, the effect of VEGF on radiosensitivity of NPC cells was investigated through xenograft model, furthermore, immunohistochemistry and TUNEL assay were used to further verify the relationship between autophagy and radiosensitivity in NPC after VEGF depletion.Results: Downregulation of VEGF significantly inhibited cell proliferation and induced apoptosis of CNE-2R cells after radiotherapy in vitro and in vivo. In addition, VEGF knockdown not only decreased autophagy level, but also delayed the DNA damage repair in CNE-2R cells after irradiation. Mechanistically, silencing VEGF suppressed autophagy through the activation of mTOR pathway.Conclusion: VEGF depletion increased radiosensitivity of NPC radioresistant cell CNE-2R by suppressing autophagy via the activation of mTOR pathway.

scholarly journals USP7 inhibition induces apoptosis in glioblastoma by enhancing ubiquitination of ARF4

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tingzheng Pan ◽  
Xuetao Li ◽  
Yanyan Li ◽  
Zhennan Tao ◽  
Hui Yao ◽  
...  
Keyword(s):  
Western Blotting ◽  
Xenograft Model ◽  
Specific Inhibitor ◽  
In Vivo Experiments ◽  
Apoptosis Assay ◽  
Specific Protease ◽  
Targeted Inhibition ◽  
Oncogenic Protein

Abstract Background Glioblastomas (GBMs) are grade IV central nervous system tumors characterized by a poor prognosis and a short median overall survival. Effective induction of GBM cell death is difficult because the GBM cell population is genetically unstable, resistant to chemotherapy and highly angiogenic. In recent studies, ubiquitin-specific protease 7 (USP7) is shown to scavenge ubiquitin from oncogenic protein substrates, so effective inhibition of USP7 may be a potential key treatment for GBM. Methods Immunohistochemistry and western blotting were used to detect the expression of USP7 in GBM tissues. In vitro apoptosis assay of USP7 inhibition was performed by western blotting, immunofluorescence, and flow cytometry. Anti-apoptotic substrates of USP7 were defined by Co-IP and TMT proteomics. Western blotting and IP were used to verify the relationship between USP7 and its substrate. In an in vivo experiment using an intracranial xenograft model in nude mice was constructed to assess the therapeutic effect of target USP7. Results Immunohistochemistry and western blotting confirmed that USP7 was significantly upregulated in glioblastoma samples. In in vitro experiments, inhibition of USP7 in GBM induced significant apoptosis. Co-IP and TMT proteomics identified a key anti-apoptotic substrate of USP7, ADP-ribosylation factor 4 (ARF4). Western blotting and IP confirmed that USP7 interacted directly with ARF4 and catalyzed the removal of the K48-linked polyubiquitinated chain that binded to ARF4. In addition, in vivo experiments revealed that USP7 inhibition significantly suppressed tumor growth and promoted the expression of apoptotic genes. Conclusions Targeted inhibition of USP7 enhances the ubiquitination of ARF4 and ultimately mediates the apoptosis of GBM cells. In a clinical sense, P5091 as a novel specific inhibitor of USP7 may be an effective approach for the treatment of GBM.

scholarly journals Upregulation of ERK-EGR1-heparanase axis by HDAC inhibitors provides targets for rational therapeutic intervention in synovial sarcoma

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Cinzia Lanzi ◽  
Enrica Favini ◽  
Laura Dal Bo ◽  
Monica Tortoreto ◽  
Noemi Arrighetti ◽  
...  
Keyword(s):  
Synovial Sarcoma ◽  
Cell Response ◽  
Histone Deacetylases ◽  
Molecular Mechanisms ◽  
Combined Treatment ◽  
Single Agent ◽  
Hdac Inhibitors ◽  
Xenograft Model

Abstract Background Synovial sarcoma (SS) is an aggressive soft tissue tumor with limited therapeutic options in advanced stage. SS18-SSX fusion oncogenes, which are the hallmarks of SS, cause epigenetic rewiring involving histone deacetylases (HDACs). Promising preclinical studies supporting HDAC targeting for SS treatment were not reflected in clinical trials with HDAC inhibitor (HDACi) monotherapies. We investigated pathways implicated in SS cell response to HDACi to identify vulnerabilities exploitable in combination treatments and improve the therapeutic efficacy of HDACi-based regimens. Methods Antiproliferative and proapoptotic effects of the HDACi SAHA and FK228 were examined in SS cell lines in parallel with biochemical and molecular analyses to bring out cytoprotective pathways. Treatments combining HDACi with drugs targeting HDACi-activated prosurvival pathways were tested in functional assays in vitro and in a SS orthotopic xenograft model. Molecular mechanisms underlying synergisms were investigated in SS cells through pharmacological and gene silencing approaches and validated by qRT-PCR and Western blotting. Results SS cell response to HDACi was consistently characterized by activation of a cytoprotective and auto-sustaining axis involving ERKs, EGR1, and the β-endoglycosidase heparanase, a well recognized pleiotropic player in tumorigenesis and disease progression. HDAC inhibition was shown to upregulate heparanase by inducing expression of the positive regulator EGR1 and by hampering negative regulation by p53 through its acetylation. Interception of HDACi-induced ERK-EGR1-heparanase pathway by cell co-treatment with a MEK inhibitor (trametinib) or a heparanase inhibitor (SST0001/roneparstat) enhanced antiproliferative and pro-apoptotic effects. HDAC and heparanase inhibitors had opposite effects on histone acetylation and nuclear heparanase levels. The combination of SAHA with SST0001 prevented the upregulation of ERK-EGR1-heparanase induced by the HDACi and promoted caspase-dependent cell death. In vivo, the combined treatment with SAHA and SST0001 potentiated the antitumor efficacy against the CME-1 orthotopic SS model as compared to single agent administration. Conclusions The present study provides preclinical rationale and mechanistic insights into drug combinatory strategies based on the use of ERK pathway and heparanase inhibitors to improve the efficacy of HDACi-based antitumor therapies in SS. The involvement of classes of agents already clinically available, or under clinical evaluation, indicates the transferability potential of the proposed approaches.

TAS-117, a Novel Selective Akt Inhibitor Demonstrates Significant Growth Inhibition in Multiple Myeloma Cells in Vitro and in Vivo

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 942-942 ◽  
Author(s):  
Naoya Mimura ◽  
Hiroto Ohguchi ◽  
Diana Cirstea ◽  
Francesca Cottini ◽  
Gullu Topal Gorgun ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Drug Resistance ◽  
Cell Growth ◽  
Board Of Directors ◽  
Cell Lines ◽  
Akt Inhibitor ◽  
Advisory Committees ◽  
Significant Growth Inhibition

Abstract Abstract 942 The PI3K/Akt pathway mediates multiple myeloma (MM) cell growth and drug resistance, and targeting this molecule is a promising therapeutic option. In this study, we examined anti-MM activities of TAS-117 (TAIHO PHARMACEUTICAL CO., LTD., JAPAN), a selective potent Akt inhibitor in MM cell lines including MM.1S, MM.1R, OPM1 and H929 cells with high level of baseline Akt phosphorylation. TAS-117 induced significant growth inhibition in these cell lines, associated with downregulation of phosphorylation (Ser473 and Thr308) of Akt and downstream molecule FKHR/FKHRL1, without cytotoxicity in normal peripheral blood mononuclear cells. TAS-117 triggered G0/G1 arrest followed by apoptosis, evidenced by increased annexin V-positive cells, in both MM.1S and H929 cell lines. Apoptosis was further confirmed by cleavage of caspase-8, -3 and PARP. Interestingly, TAS-117 also induced: autophagy, evidenced by increased LC3-II; as well as endoplasmic reticulum (ER) stress, confirmed by induction of phospho-eIF2α, phospho-IRE1α and a molecular chaperone BiP/GRP78. Since the bone marrow (BM) microenvironment plays a crucial role in MM cell pathogenesis including drug resistance, we further examined the effect of TAS-117 in the presence of BM stromal cells (BMSCs). TAS-117 induced significant cytotoxicity in MM cells even in the presence of BMSCs, associated with downregulation of phospho-Akt. Importantly, TAS-117 inhibited secretion of IL-6 from BMSCs, and exogenous IL-6 and IGF-1 did not block cytotoxicity induced by this agent. We have previously shown the bortezomib activates Akt, and that Akt inhibition with bortezomib triggers synergistic MM cell cytotoxicity. TAS-117 enhanced bortezomib-induced cytotoxicity in MM.1S cells, associated with increased CHOP followed by PARP cleavage, suggesting that TAS-117 augments bortezomib-induced ER stress and apoptotic signaling. TAS-117 also enhanced cytotoxicity induced by other therapeutic agents (ie, rapamycin, dexamethasone, 17-AAG) in MM.1S cells. Finally, we examined anti-MM activities of TAS-117 in a xenograft murine model. Oral administration of TAS-117 for 14 days significantly inhibited growth of H929 plasmacytoma and was well tolerated. Taken together, the novel and selective Akt inhibitor TAS-117 blocks MM cell growth in vitro and in vivo, providing the preclinical framework for clinical evaluation of this agent to improve patient outcome in MM. Disclosures: Shimomura: TAIHO PHARMACEUTICAL CO., LTD.: Employment. Utsugi:TAIHO PHARMACEUTICAL CO., LTD.: Membership on an entity's Board of Directors or advisory committees. Anderson:Celgene, Millennium, BMS, Onyx: Membership on an entity's Board of Directors or advisory committees; Acetylon, Oncopep: Scientific Founder, Scientific Founder Other.

scholarly journals Ubiquitin-Like Protein UBD Promotes Cell Proliferation in Colorectal Cancer by Facilitating p53 Degradation

2021 ◽  
Vol 11 ◽  
Author(s):  
Hongbin Su ◽  
Mengdi Qin ◽  
Qiang Liu ◽  
Bo Jin ◽  
Xianjun Shi ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Western Blotting ◽  
Xenograft Model ◽  
Proteasome Inhibition ◽  
Tissue Samples ◽  
Functional Changes ◽  
Tumor Tissues ◽  
Expression Plasmids

PurposeUbiquitin D (UBD) is a member of the ubiquitin-like modifier (UBL) family and is highly expressed in a variety of cancers including colorectal cancer (CRC). However, the mechanisms of its regulatory roles in CRC are largely elusive. In this study, we revealed the effect of UBD on the proliferation of CRC.MethodsThe expression of UBD in clinical tissue samples of CRC and seven CRC cell lines was detected using qRT-PCR, immunohistochemistry (IHC) and Western blotting. CCK-8, colony formation, EdU and flow cytometry assays were used to detect the functional changes of CRC cells transfected with UBD stable expression plasmids in vitro. A xenograft model was constructed to assess the effect of UBD on the growth of CRC cells in vivo. The connection between UBD and p53 was analyzed using Western blotting, immunoprecipitation, proteasome inhibition assay and Cycloheximide (CHX) chase assay.ResultsUBD was overexpressed in CRC tumor tissues compared with nontumor tissues, and its overexpression was positively associated with the tumor size and TNM stage of CRC patients. Functionally, UBD significantly accelerated CRC cell viability and proliferation in vitro and promoted tumorigenesis in vivo. Mechanistically, UBD interacted with p53 in CRC cells, downregulated the expression of p53 by regulating its degradation, shortened the p53 half-life, thereby further affecting the decrease in p21 and the increase in Cyclin D1, Cyclin E, CDK2, CDK4 and CDK6. Moreover, in vivo experiments showed that UBD-induced tumor growth in nude mice was dependent on a decrease in p53.ConclusionsOur study proved that UBD mediates the degradation of p53, thereby facilitating the growth of CRC cells and ultimately promoting the progression of CRC. Therefore, UBD may be a potential therapeutic target and a promising prognostic biomarker for CRC.

scholarly journals Circular RNA circASPM Promotes the Progression of Glioblastoma by Acting as a Competing Endogenous RNA to Regulate miR-130b–3p/E2F1 Axis

2020 ◽  
Author(s):  
Dianqi Hou ◽  
Zhenlin Wang ◽  
Haimeng Li ◽  
Juan Liu ◽  
Yaohua Liu ◽  
...  
Keyword(s):  
Western Blotting ◽  
Circular Rna ◽  
Luciferase Reporter ◽  
Circular Rnas ◽  
Primary Malignancy ◽  
Rna Immunoprecipitation ◽  
Western Blotting Assay

Abstract background: Glioblastoma Multiform (GBM) is the primary malignancy with the highest incidence and worst prognosis in the adult CNS. Circular RNAs (circRNAs) are a novel and widely diverse class of endogenous non-coding RNAs that can promote or inhibit gliomagenesis. Our study aimed to explore the role of circASPM in GBM and its molecular mechanism.Methods: Levels of circASPM, miR-130b-3p and E2F1 were determined by quantitative real-time PCR (qRT-PCR) or western blotting assay. MTS, Edu, neurospheres formation and extreme limiting dilution assays were used to detect the tumorigenesis and proliferation of GSCs in vitro. The interactions between miR-130b-3p and circASPM or E2F1 was demonstrated via qPCR, western blotting, dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Xenograft experiments was used to analyze tumor growth in vivo.Results: CircASPM was overexpressed in GBM and could promote the tumorigenesis and proliferation of GSCs both in vitro and in vivo. Mechanistically, circASPM up-regulated the expression of E2F1 in GSCs via miR-130b-3p sponging. We furtherly demonstrated that circAPSM could promote the GSCs proliferation via E2F1 up-regulating. Therefore, our study identified a novel circRNA and its possible mechanism in the development and tumorigenesis of GBM.Conclusions: CircASPM can promote GBM progression via regulating miR-130b-3p/E2F1 axis, suggesting that circAPSM could provide an effective biomarker for GBM diagnosis and prognostic evaluation and possibly being used for molecular targeted therapy.

scholarly journals The Autophagy Inhibitor Chloroquine, Alone or in Combination with mTOR Inhibitors, Displays Anti-Tumor Effects in In Vitro and In Vivo Lung Carcinoid Models

Cancers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 6327
Author(s):  
Adi Knigin ◽  
Shani Avniel-Polak ◽  
Gil Leibowitz ◽  
Kira Oleinikov ◽  
David J. Gross ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Tumor Cell ◽  
Cell Survival ◽  
Western Blotting ◽  
Xenograft Model ◽  
Neuroendocrine Neoplasms ◽  
In Vivo Models ◽  
Murine Xenograft Model

(1) Background: Neuroendocrine neoplasms of the lung (LNENs, lung carcinoids) are often diagnosed at an advanced stage when they are not surgically curable, and treatment options are limited. One of the approved options for treating inoperable tumors is everolimus—an mTOR inhibitor (mTORi). Activation of mTOR, among many other effects, inhibits autophagy, which is a cell survival mechanism in general, and in tumor cells in particular. Everolimus may paradoxically encourage cancer cell survival. In practice, the drug inhibits tumor development. Chloroquine (CQ) is a known antimalarial compound that inhibits autophagy. Our research is focused on the hypothesis that autophagy plays a key role in the development of tumor resistance to mTORi, and that the addition of autophagy inhibitors to mTORi exerts a synergistic effect on suppressing tumor cell proliferation. We have recently demonstrated that the combination of CQ with different mTORi increases their potency compared with mTORi alone in both in vitro and in vivo models of pancreatic NENs. In this study, we examined the effects of CQ and mTORi on in vitro and in vivo LNEN models. Aims: Testing the effects of CQ together with mTORi on cell proliferation, apoptosis, and autophagy in in vitro and in vivo LNEN models. (2) Methods: The NCI-H727 LNEN cells were treated with CQ ± mTORi. Cells’ viability and proliferation were measured using XTT and Ki-67 FACS staining. The effects of the treatments on the mTOR pathway and autophagy were examined using Western blotting. Cytotoxicity was measured using a cytotoxicity kit; apoptosis was measured by PI FACS staining and Western blotting. We further established an LNEN subcutaneous murine xenograft model and evaluated the effects of the drugs on tumor growth. (3) Results: CQ alone suppressed LNEN cells’ viability and proliferation and increased their cytotoxicity and apoptosis; these effects were augmented when CQ was added to an mTORi. We also showed the possible mechanisms for these results: on the one hand we could see a decrease in P62 levels and the absence of LC3-II (both inversely related to autophagy) following treatment with the mTORi, and on the other hand we could demonstrate an increase in their levels when CQ was added. The effect was less apparent in the murine xenograft model. (4) Conclusions: By inhibiting autophagy and inducing apoptosis, CQ suppresses tumor cell growth in LNENs. CQ potentiates mTORi effects, implying that further studies are needed in order to elucidate its possible role in tumor inhibition in patients with LNENs.

scholarly journals Dehydroxymethylepoxyquinomicin, a Novel Nuclear Factor-κB Inhibitor, Enhances Antitumor Activity of Taxanes in Anaplastic Thyroid Cancer Cells

Endocrinology ◽  
2008 ◽  
Vol 149 (11) ◽  
pp. 5357-5365 ◽  
Author(s):  
Zhaowei Meng ◽  
Norisato Mitsutake ◽  
Masahiro Nakashima ◽  
Dmytro Starenki ◽  
Michiko Matsuse ◽  
...  
Keyword(s):  
Thyroid Cancer ◽  
Nuclear Translocation ◽  
Combined Treatment ◽  
Xenograft Model ◽  
Anaplastic Thyroid Cancer ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Antitumor Activities

Nuclear factor κB (NF-κB), as an antiapoptotic factor, crucially affects the outcomes of cancer treatments, being one of the major culprits of resistance to chemotherapy. In this study, we investigated whether dehydroxymethylepoxyquinomicin (DHMEQ), a novel NF-κB inhibitor, can enhance antitumor activities of taxanes in anaplastic thyroid cancer (ATC) cells. Taxanes induced NF-κB activation in ATC cells, which could compromise the therapeutic effect of the drugs. However, DHMEQ, by inhibiting the nuclear translocation of NF-κB, completely suppressed the DNA binding capacities of NF-κB and lowered the levels of nuclear NF-κB protein. Compared with single treatment (either taxane or DHMEQ), the combined treatment strongly potentiated apoptosis, confirmed by cell survival assay; Western blotting for poly (ADP-ribose) polymerase, caspase 3, X-linked inhibitor of apoptosis, and survivin; and flow cytometry for annexin V. Furthermore, we also demonstrate for the first time that the combined treatment showed significantly greater inhibitory effect on tumor growth in a nude mice xenograft model. These findings suggest that taxanes are able to induce NF-κB activation in ATC cells, which could attenuate antitumor activities of the drugs, but inhibition of NF-κB by DHMEQ creates a chemosensitive environment and greatly enhances apoptosis in taxanes-treated ATC cells in vitro and in vivo. Thus, DHMEQ may emerge as an attractive therapeutic strategy to enhance the response to taxanes in ATCs.

scholarly journals Cynaropicrin Shows Antitumor Progression Potential in Colorectal Cancer Through Mediation of the LIFR/STATs Axis

2021 ◽  
Vol 8 ◽  
Author(s):  
Dandan Zheng ◽  
Yu Zhu ◽  
Yili Shen ◽  
Sisi Xiao ◽  
Lehe Yang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Western Blotting ◽  
Cell Function ◽  
Xenograft Model ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Leukemia Inhibitory Factor Receptor ◽  
Antitumor Effects

BackgroundColorectal cancer (CRC) is the second deadliest malignant disease in the world and the leukemia inhibitory factor receptor/signal transducers and activators of transcriptions (LIFR/STATs) signaling axis plays an important role in the molecular biology of CRC.MethodsCell function tests were performed to observe the inhibitory effect of cynaropicrin on human CRC cells (RKO, HCT116, and DLD-1). Expression levels of LIFR, P-STAT3, P-STAT4, and apoptotic proteins were detected by Western blotting. Immunoprecipitation confirmed the presence of LIFR/STAT3/STAT4 complex. Cell immunofluorescence assay was used to observe the subcellular localization of STAT3 and STAT4. In vivo efficacy of cynaropicrin was evaluated by a xenotransplantation model in nude mice.ResultsCynaropicrin significantly reduced the survival ability of human CRC cells and promoted apoptosis in a dose-dependent manner. Western blotting results suggested that the antitumor effects of cynaropicrin might be mediated by inhibition of the LIFR/STATs axis. Cynaropicrin reduced the formation of STAT3/STAT4 heterodimers and blocked their entry into the nucleus. Cynaropicrin also suppressed tumor growth in the xenograft model.ConclusionThe results showed that cynaropicrin exerted a strong inhibitory effect on CRC in vitro and in vivo. Our study concluded that cynaropicrin has potential application prospects in the field of anti-CRC therapy.

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