IMMU-06. DELTA-24-RGD EXPRESSING POSITIVE IMMUNE MODULATORS SHOW ANTI-DIPG EFFECT AND INCREASE TUMOR IMMUNE INFILTRATION

Abstract Diffuse Intrinsic Pontine Gliomas (DIPG) are aggressive pediatric brain tumors that arise in the pons of children, being the leading cause of pediatric death caused by cancer. We have previously demonstrated that Delta-24-RGD administration is safe and efficacious in DIPG preclinical models, indicating that it could be a good candidate as therapeutic approach for DIPG. However, our data underscore that there is still room to improve the anti-DIPG effect obtained with Delta-24-RGD. For that purpose, we have constructed three new virus by engineering Delta-24-RGD with different T cell activators: 4-1BBL (Delta-24-ACT), OX40-L (Delta-24-RGDOX) and GITRL (Delta-24-GREAT), to further increase the immune response generated by the viral effect. In vitro, the three virus were able to infect murine and human DIPG cell lines, produce oncolytic effect in a dose-dependent manner and express the corresponding functional ligand (4-1BBL, OX40L or GITRL) in the membrane of infected cells (almost 100% of cells expressing them at 10 MOIs). As expected, viral replication was optimal in human cell lines but semipermissive in murine cells. In vivo, the intratumoral administration of armed oncolytic viruses was safe and significantly increased survival of mice bearing orthotopic DIPG murine tumors, leading to long-term survivors. In addition, we analyzed the effect of the virus in the tumor microenvironment by flow cytometry and immunohistochemistry, which indicated that there was a significant increase of immune infiltration in brains of treated mice. Moreover, the immune infiltrated showed a functional active phenotype. Although deeper characterization is needed, these data show that the incorporation of a positive immune modulator into Delta-24-RGD could improve the oncolytic effect of the virus by boosting the immune response, while maintaining a safe profile in immunocompetent models offering a feasible option treatment for DIPG.

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Sarcoma IL-12 overexpression facilitates NK cell immunomodulation

Scientific Reports ◽

10.1038/s41598-021-87700-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mary Jo Rademacher ◽

Anahi Cruz ◽

Mary Faber ◽

Robyn A. A. Oldham ◽

Dandan Wang ◽

...

Keyword(s):

Immune Response ◽

Cell Lines ◽

Nk Cell ◽

Autologous Tumor ◽

Murine Models ◽

Lentiviral Transduction ◽

Ifn Γ ◽

Human Sarcoma

AbstractInterleukin-12 (IL-12) is an inflammatory cytokine that has demonstrated efficacy for cancer immunotherapy, but systemic administration has detrimental toxicities. Lentiviral transduction eliciting IL-12-producing human sarcoma for autologous reintroduction provides localized delivery for both innate and adaptive immune response augmentation. Sarcoma cell lines and primary human sarcoma samples were transduced with recombinant lentivirus engineering expression of human IL-12 (hu-IL-12). IL-12 expressing sarcomas were assessed in vitro and in vivo following implantation into humanized NSG and transgenic human IL-15 expressing (NSG.Tg(Hu-IL-15)) murine models. Lentiviral transduction (LV/hu-IL-12) of human osteosarcoma, Ewing sarcoma and rhabdomyosarcoma cell lines, as well as low-passage primary human sarcomas, engendered high-level expression of hu-IL-12. Hu-IL-12 demonstrated functional viability, eliciting specific NK cell-mediated interferon-γ (IFN-γ) release and cytotoxic growth restriction of spheroids in vitro. In orthotopic xenograft murine models, the LV/hu-IL-12 transduced human sarcoma produced detectable IL-12 and elicited an IFN-γ inflammatory immune response specific to mature human NK reconstitution in the NSG.Tg(Hu-IL-15) model while restricting tumor growth. We conclude that LV/hu-IL-12 transduction of sarcoma elicits a specific immune reaction and the humanized NSG.Tg(Hu-IL-15) xenograft, with mature human NK cells, can define in vivo anti-tumor effects and systemic toxicities. IL-12 immunomodulation through autologous tumor transduction and reintroduction merits exploration for sarcoma treatment.

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IMMU-14. ONCOLYTIC VIRUS EXPRESSING A POSITIVE IMMUNE CHECKPOINT MODULATOR AS A THERAPEUTIC APPROACH FOR DIPG

Neuro-Oncology ◽

10.1093/neuonc/noz175.508 ◽

2019 ◽

Vol 21 (Supplement_6) ◽

pp. vi122-vi122

Author(s):

Virginia Laspidea ◽

Montse Puigdelloses ◽

Ignacio Iñigo-Marco ◽

Marc Garcia-Moure ◽

Iker Ausejo ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

Cell Death ◽

Cell Lines ◽

Oncolytic Virus ◽

Murine Models ◽

Antitumoral Effect ◽

Infected Cells

Abstract Diffuse intrinsic pontine glioma (DIPG) is an aggressive brain tumor, being the leading cause of pediatric death caused by cancer. We previously showed that administration of the oncolytic virus Delta-24-RGD to DIPG murine models was safe and led to an increase in the median survival of these animals. However, not all the animals responded, underscoring the need to improve this therapy. In order to increase the antitumoral effect of the virus, we have engineered Delta-24-RGD with the costimulatory ligand 4-1BBL (Delta24-ACT). 4-1BB is a costimulatory receptor that promotes the survival and expansion of activated T cells, and the generation and maintenance of memory CD8+ T cells. In this project, we evaluated the oncolytic effect of Delta24-ACT and the antitumor immune response in DIPG murine models. In vitro, Delta24-ACT was able to infect and induce cell death in a dose-dependent manner in murine DIPG cell lines. In addition, Delta24-ACT was able to replicate in these tumor cells and to express viral proteins. Moreover, infected cells expressed 41BBL in their membranes. Delta24-ACT could induce immunogenic cell death due to an increased secretion of ATP and calreticulin translocation to the membrane of infected cells (in no-infected cells it located in the ER), DAMPs that can trigger the immune response activation. In vivo, Delta24-ACT demonstrated to be safe in all the tested doses and was able to induce a significant increase in the median survival of the treated animals. Moreover, long-term survivors display immunological memory. Delta24-ACT treatment led to antitumoral effect in DIPG murine cell lines in vitro. Of significance, we have demonstrated that in vivo administration of Delta24-ACT is safe and results in an enhanced antitumor effect. Future in vivo studies will explore the underlying immune mechanism of the virus.

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The Histone Deacetylase (HDAC) Inhibitor Entinostat (SNDX-275) Targets Hodgkin Lymphoma through a Dual Mechanism of Immune Modulation and Apoptosis Induction.

Blood ◽

10.1182/blood.v114.22.1562.1562 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1562-1562 ◽

Cited By ~ 3

Author(s):

Noor M Khaskhely ◽

Daniela Buglio ◽

Jessica Shafer ◽

Catherine M. Bollard ◽

Anas Younes

Keyword(s):

Immune Response ◽

Cell Death ◽

Protein Expression ◽

Cell Lines ◽

Dependent Manner ◽

Chemokine Production ◽

Apoptosis Pathway ◽

Gene And Protein Expression ◽

Combination Studies

Abstract Abstract 1562 Poster Board I-585 Purpose SNDX-275 is an oral, class 1 isoform selective HDACi. Phase 1 studies in leukemia demonstrated the agent has a long half-life and that weekly or every other week dosing is sufficient for antitumor activity. Based on recent favorable in vitro and in vivo activity of several HDAC inhibitors in HL, we investigated the in vitro activity of SNDX275 in HL-derived cell lines. Methods For apoptosis and gene expression analysis 05 × 106 cells were incubated with 0.1-2 μM of SNDX-275 for 24-72 hours before they were examined for proliferation and cell death by the MTS assay and the annexin-PI and FACS analysis. For combination studies, cells were incubated with 0.1-2 uM of SNDX-275 and 1-20 nM of either gemcitabine or bortezomib for 48-72 hours. Gene and protein expression were measured by RT-PCR, western blot, and immunohistochemistry. SNDX-275 effects on a panel of 30 cytokines and chemokines was assayed on 05 × 106 cells after incubation of 48 hrs using a multiplex assay. Results SNDX-275 induced cell death in a dose and time dependent manner with an IC50 of 0.4 μM. At the molecular level, SNDX-275 increased H3 acetylation, up-regulated p21 protein expression, and activated the intrinsic apoptosis pathway by down-regulating the anti-apoptotic X-linked inhibitor or apoptosis (XIAP) protein, which was associated with activation of caspase 9 and 3. Combination studies demonstrated that SNDX-275 had synergistic effects when combined with gemcitabine and bortezomib. To further investigate the potential for SNDX-275 activity in HL we measured the effect of SNDX-275 on pathways that may contribute to an anti-tumor immune response. Dysregulated cytokine/chemokine production has been shown to contribute to HL pathology, including immune tolerance of the cancer cells. SNDX-275 increased IL12 p40-70, IP10, and RANTES, and decreased the level of IL13 and IL4, thus favoring Th1-type cytokines/chemokines. In addition, recent data has demonstrated that a variety of epigenetic-modulating drugs may up-regulate the expression of cancer testis tumor associated antigens, leading to a favorable immune response. None of the lines expressed the CTAs without induction. SNDX275 was able to induce CTA expression of SSX2 in L428 but not HDLM2 whereas MAGE-A was induced in both HL cell lines. NY-ESO expression was not induced. Conclusions Our studies demonstrate that SNDS-275 has dual effect on apoptotic and immunomodulatory pathways in HL. Furthermore, this data demonstrates that SNDX-275 may upregulate CTAs suggesting that this treatment may render the tumor more immunogeneic and susceptible to immune mediated killing with tumor-specific cytotoxic T lymphocytes. The selectivity profile of SNDX-275 also suggests that HDAC1 and 2 are the primary targets for HDAC inhibition in these cells. Phase 2 studies with SNDX-275 in HL are ongoing. Disclosures Younes: MethylGene: Honoraria, Research Funding.

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Further Preclinical Studies with APR-246, a Novel Anticancer Compound Currently in Clinical Trials for Hematological Malignancies and Prostate Cancer.

Blood ◽

10.1182/blood.v114.22.3773.3773 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3773-3773

Author(s):

Nina Mohell ◽

Charlotta Liljebris ◽

Jessica Alfredsson ◽

Ylva Lindman ◽

Maria Uustalu ◽

...

Keyword(s):

Clinical Trials ◽

Cancer Cells ◽

Cell Lines ◽

Cancer Cell ◽

Ex Vivo ◽

Cancer Cell Lines ◽

Solid Cancer ◽

Dependent Manner

Abstract Abstract 3773 Poster Board III-709 Introduction The tumor suppressor protein p53 induces cell cycle arrest and/or apoptosis in response to various forms of cellular stress, through transcriptional regulation of a large number of down stream target genes. p53 is frequently mutated in cancer, and cancer cells carrying defects in the p53 protein are often more resistant to conventional chemotherapy. Thus, restoration of the wild type function to mutant p53 appears to be a new attractive strategy for cancer therapy. APR-246 is a novel small molecule quinuclidinone compound that has been shown to reactivate non-functional p53 and induce apoptosis. Although the exact molecular mechanism remains to be determined, recent results suggest that an active metabolite of APR-246 alkylates thiol groups in the core domain of p53, which promotes correct folding of p53 and induces apoptosis (Lambert et al., Cancer Cell 15, 2009). Currently, APR-246 is in Phase I/IIa clinical trials for hematological malignancies and prostate cancer. In the present abstract results from in vitro, ex vivo and in vivo preclinical studies with APR-246 are presented. Results The lead compound of APR-246, PRIMA-1 (p53 reactivation and induction of massive apoptosis), was originally identified by a cellular screening of the NCI library for low molecular weight compounds (Bykov et al., Nat. Med., 8, 2002). Further development and optimization of PRIMA-1 led to the discovery of the structural analog APR-246 (PRIMA-1MET), with improved drug like and preclinical characteristics. In in vitro experiments APR-246 reduced cell viability (WST-1 assay) in a large number of human cancer cell lines with various p53 status, including several leukemia (CCRF-CEM, CEM/VM-1, KBM3), lymphoma (U-937 GTP, U-937-vcr), and myeloma (RPMI 8226/S, 8226/dox40, 8226/LR5) cell lines, as well as many solid cancer cell lines, including osteosarcoma (SaOS-2, SaOS-2-His273,U-2OS), prostate (PC3, PC3-His175, 22Rv1), breast (BT474, MCF-7, MDA-MB-231), lung (H1299, H1299-His175) and colon cancer (HT-29). In human osteosarcoma cell lines APR-246 reduced cell viability and induced apoptosis (FLICA caspase assay) in a concentration dependent manner being more potent in the p53 mutant (SaOS-2-His273) than in the parental p53 null (SaOS-2) cells. The IC50 values (WST-1 assay) were 14 ± 3 and 27 ± 5 μM, respectively (n=35). In in vivo subcutaneous xenograft studies in SCID (severe combined immunodeficiency) mice APR-246 reduced growth of p53 mutant SaOS-2-His273 cells in a dose-dependent manner, when injected i.v. twice daily with 20 -100 mg/kg (64 – 76% inhibition). An in vivo anticancer effect of APR-246 was also observed in hollow-fiber test with NMRI mice using the acute myeloid leukemia (AML) cell line MV-4-11. An ex vivo cytotoxic effect of APR-246 and/or its lead compound PRIMA-1 has also been shown in primary cells from AML and CLL (chronic lymphocytic leukemia) patients, harbouring both hemizygously deleted p53 as well as normal karyotype (Nahi et al., Br. J. Haematol., 127, 2004; Nahi et al., Br. J. Haematol., 132, 2005; Jonsson-Videsater et al., abstract at this meeting). APR-246 was also tested in a FMCA (fluorometric microculture assay) test using normal healthy lymphocytes (PBMC) and cancer lymphocytes (CLL). It was 4-8 fold more potent in killing cancer cells than normal cells, indicating a favorable therapeutic index. This is in contrast to conventional cytostatics that often show negative ratio in this test. Furthermore, when tested in a well-defined panel of 10 human cancer cell lines consisting of both hematological and solid cancer cell lines, the cytotoxicity profile/activity pattern of APR-246 differed from common chemotherapeutic drugs (correlation coefficient less than 0.4), suggesting a different mechanism of action. Conclusion In relevant in vitro, in vivo and ex vivo cancer models, APR-246 showed unique pharmacological properties in comparison with conventional cytostatics, by being effective also in cancer cells with p53 mutations and by demonstrating tumor specificity. Moreover, in experimental safety/toxicology models required to start clinical trials, APR-246 was non toxic at the predicted therapeutic plasma concentrations. Thus, APR-246 appears to be a promising novel anticancer compound that may specifically target cancer cells in patients with genetic abnormality associated with poor prognosis. Disclosures: Mohell: Aprea AB: Employment. Liljebris:Aprea AB: Employment. Alfredsson:Aprea AB: Employment. Lindman:Aprea AB: Employment. Uustalu:Aprea AB: Employment. Wiman:Aprea AB: Co-founder, shareholder, and member of the board. Uhlin:Aprea AB: Employment.

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Inhibition of Tumor Cell Proliferation In Vitro by Benzamide Derivatives

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.997.225 ◽

2014 ◽

Vol 997 ◽

pp. 225-228 ◽

Cited By ~ 1

Author(s):

Yan Ling Wu ◽

Li Wen Shen ◽

Yan Ping Ding ◽

Yoshimasa Tanaka ◽

Wen Zhang

Keyword(s):

Tumor Cell ◽

Cell Lines ◽

Malignant Tumors ◽

Dependent Manner ◽

Tumor Cell Lines ◽

Lead Compounds ◽

Proliferative Effect ◽

Benzamide Derivatives

Benzamide derivatives have been shown to have antitumor activity in various tumor cell lines in vitro as well as in vivo. In this study, we examined the anti-proliferative effect of four benzamide derivativeson Hela, H7402, and SK-RC-42 tumor cell lines in vitro by means of Real-Time cell assay (RTCA), and found that four benzamide derivatives suppressed proliferation of tumor cells in a time-and dose-dependent manner. The anti-proliferative activity of benzamide derivatives demonstrated that theycould be promising lead compounds for developing therapeutic agents for malignant tumors.

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Epigenetic Inactivation of Acetyl-Co A acetyltransferase 1 promotes the proliferation and metastasis of nasopharyngeal carcinoma via decreasing ketogenesis

10.21203/rs.3.rs-69360/v1 ◽

2020 ◽

Author(s):

Yunliang Lu ◽

Xiaohui Zhou ◽

Weilin Zhao ◽

Zhipeng Liao ◽

Bo Li ◽

...

Keyword(s):

Cell Lines ◽

Colony Formation ◽

Ketone Body ◽

Epithelial Mesenchymal Transition ◽

Cpg Island ◽

Dependent Manner ◽

Mesenchymal Transition ◽

Ketone Body Metabolism

Abstract Background Acy1 Coenzyme A Acyltransferases1 (ACAT1) is a key enzyme in the metabolism of ketone bodies, but its expression and biological function in the pathogenesis of NPC remains underexplored. Methods The mRNA and protein expression levels of ACAT1 in NPC and normal control tissues were analyzed by qPCR and immunohistochemistry staining, respectively. GEO database was applied for meta-analysis of ACAT1 mRNA expression and DNA promoter methylation. The role of ACAT1 in NPC proliferation was examined by CCK8 and colony formation assays in vitro and tumorigenicity in vivo. The wound healing and transwell assays were used for analyzing the migratory and invasive ability. cDNA microarray analysis was performed to identify the genes involved in epithelial-mesenchymal transition and dysregulated by ACAT1. These changes were further confirmed by western blot. Results We found that ACAT1 is inactivated in NPC cell lines and primary tissues. DNA microarray data showed higher methylation in the CpG island region of ACAT1 in NPC than normal tissues. The demethylating reagent 5-aza-dC significantly restored the transcription of ACAT1 in NPC cell lines, suggesting that ACAT1 was inactivated by DNA promoter hypermethylation. Ectopic overexpression of ACAT1 remarkably suppressed the proliferation and colony formation of NPC cells in vitro. As well, the tumorigenesis of NPC cells overexpressing ACAT1 was decreased in vivo. In addition, the migratory and invasive capacities of NPC cells was inhibited by ACAT1 overexpression. Importantly, the higher level of ACAT1 was accompanied by an increased expression of CDH1, EPCAM, and a decreased expression of vimentin and SPARC. This strongly indicates that ACAT1 is able to affect the epithelial-mesenchymal transition in NPC, thereby controlling cellular motility. In addition, we found that ACAT1 expression increases the intracellular level of β-HB. Moreover, exogenous β-HB remarkably inhibits the growth of NPC cells in a dose-dependent manner. Conclusions We have discovered that the ketone body metabolism enzyme ACAT1 is epigenetically downregulated in NPC and acts as a potential tumor suppressor in NPC. Our findings highlight the possibility of using the modulation of ketone body metabolism as effective adjuvant therapy for NPC.

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An In Vivo CRISPR Screening Platform to Identify New Therapeutic Targets in AML

Blood ◽

10.1182/blood-2021-153039 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 266-266

Author(s):

Shan Lin ◽

Clement Larrue ◽

Nastassja K. Scheidegger ◽

Bo Kyung A. Seong ◽

Neekesh V Dharia ◽

...

Keyword(s):

Cell Lines ◽

Small Molecule ◽

Large Scale ◽

E3 Ligase ◽

Functional Genomic ◽

Dependent Manner ◽

Pdx Model ◽

Pdx Models

Abstract First-generation, large-scale functional genomic screens have revealed hundreds of potential genetic vulnerabilities in acute myeloid leukemia (AML), a devastating hematologic malignancy with poor overall survival. Because these large-scale genetic screens were primarily performed in vitro in established AML cell lines, their translational relevance has been debated. Therefore, we established a protocol for CRISPR screening in orthotopic xenograft models of human AML, including patient-derived-xenograft (PDX) models that are tractable for CRISPR-editing. We first defined experimental conditions necessary for an optimal in vivo screen via barcoding experiments. We determined that sub-lethal irradiation was necessary for improved barcode representation in bone marrow and to reduce mouse-to-mouse variation. Moreover, it was critical to combine samples from multiple mice to achieve complete in vivo library representation. Next, using the Broad DepMap and other publicly available functional genomic screen data, we identified 200 genes that were stronger dependencies in AML cell lines compared to all other cancer types screened. Using this list, we created a secondary library and performed parallel in vivo and in vitro screens using the MV4-11 and U937 cell lines and a PDX model. In vitro and in vivo hits were surprisingly well correlated, although a modest number of targets did not score well in vivo. Notably, dependencies identified across AML cell line models were strongly recapitulated in the PDX model, validating the application of AML cell lines for dependency discovery. Our in vivo screens nominated the mitochondria-localized RING-type ubiquitin E3 ligase MARCH5 as a potential therapeutic target in AML. Using CRISPR, we first validated this in vitro dependency on MARCH5 and determined that MARCH5 is a critical guardian to prevent apoptosis in AML. MARCH5 depletion activates the canonical mitochondrial apoptosis pathway in a BAX/BAK1-dependent manner. Multiple genome-wide screens revealed that a dependency on MARCH5 is strongly correlated with a dependency on MCL1, but not other anti-apoptotic BCL2-family members, across the AML cell lines in the screen. As observed with MCL1 inhibition, MARCH5 depletion sensitized AML cells to venetoclax, a BCL2-specific inhibitor FDA-approved in combination with a hypomethylating agent for the treatment of older adults with AML. Importantly, MARCH5 depletion diminished the venetoclax resistance induced by MCL1 overexpression but not that caused by BCLXL overexpression. Altogether, these results suggest that MARCH5 is required for maintaining MCL1 activity specifically. Since there are no small molecule inhibitors directed against MARCH5, we deployed a dTAG system as an approximation of pharmacological inhibition. This approach uses a hetero-bifunctional small molecule that binds the FKBP12 F36V-fused MARCH5 and the E3 ligase VHL, leading to the ubiquitination and proteasome-mediated degradation of the fusion protein. dTAG-MARCH5 cells were established via deleting endogenous MARCH5 by CRISPR and expressing exogenous FKBP-tagged MARCH5 protein. MARCH5 degradation with the dTAG molecule dTAG V-1 markedly impaired cell growth in vitro. Additionally, we demonstrated the utility of dTAG system in vivo using a PDX model. The combination treatment of dTAG V-1 and venetoclax elicited a much stronger anti-leukemic effect compared to the treatment with only venetoclax or dTAG V-1, further highlighting MARCH5 as a promising synergistic target for enhancing the efficacy of venetoclax in AML. Taken together, our in vivo screening approach, coupled with CRISPR-competent PDX models and dTAG-directed protein degradation, constitute a useful platform for prioritizing AML targets emerging from in vitro screens to serve as the starting point for therapy development. Disclosures Dharia: Genentech: Current Employment. Piccioni: Merck Research Laboratories: Current Employment. Stegmaier: Bristol Myers Squibb: Consultancy; KronosBio: Consultancy; AstraZeneca: Consultancy; Auron Therapeutics: Consultancy, Current equity holder in publicly-traded company; Novartis: Research Funding.

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Cytotoxic effect of Montivipera bornmuelleri’s venom on cancer cell lines: in vitro and in vivo studies

PeerJ ◽

10.7717/peerj.9909 ◽

2020 ◽

Vol 8 ◽

pp. e9909

Author(s):

Carol Haddoub ◽

Mohamad Rima ◽

Sandrine Heurtebise ◽

Myriam Lawand ◽

Dania Jundi ◽

...

Keyword(s):

Tumor Growth ◽

Cell Lines ◽

Cytotoxic Effect ◽

In Vivo Studies ◽

Dependent Manner ◽

In Vivo Testing ◽

Murine Fibrosarcoma ◽

Dose Dependent

Background Montivipera bornmuelleri’s venom has shown immunomodulation of cytokines release in mice and selective cytotoxicity on cancer cells in a dose-dependent manner, highlighting an anticancer potential. Here, we extend these findings by elucidating the sensitivity of murine B16 skin melanoma and 3-MCA-induced murine fibrosarcoma cell lines to M. bornmuelleri’s venom and its effect on tumor growth in vivo. Methods The toxicity of the venom on B16 and MCA cells was assessed using flow cytometry and xCELLigence assays. For in vivo testing, tumor growth was followed in mice after intratumoral venom injection. Results The venom toxicity showed a dose-dependent cell death on both B16 and MCA cells. Interestingly, overexpression of ovalbumin increased the sensitivity of the cells to the venom. However, the venom was not able to eradicate induced-tumor growth when injected at 100 µg/kg. Our study demonstrates a cytotoxic effect of M. bornmuelleri’s venom in vitro which, however, does not translate to an anticancer action in vivo.

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Octreotide-conjugated silver nanoparticles for active targeting of somatostatin receptors and their application in a nebulized rat model

Nanotechnology Reviews ◽

10.1515/ntrev-2022-0021 ◽

2021 ◽

Vol 11 (1) ◽

pp. 266-283

Author(s):

Ahmed A. H. Abdellatif ◽

Riaz A. Khan ◽

Ahmad H. Alhowail ◽

Abdulmajeed Alqasoumi ◽

Sultan M. Sajid ◽

...

Keyword(s):

Drug Delivery ◽

Silver Nanoparticles ◽

Cell Lines ◽

Somatostatin Receptors ◽

Somatostatin Analogs ◽

Drug Uptake ◽

Emission Spectrometry ◽

Dependent Manner

Abstract Drug uptake and distribution through cell–receptor interactions are of prime interest in reducing the adverse effects and increasing the therapeutic effectiveness of delivered formulations. This study aimed to formulate silver nanoparticles (AgNPs) conjugated to somatostatin analogs for specific delivery through somatostatin receptors (SSTRs) expressed on cells and by nebulizing the prepared AgNPs formulations into lung cells for in vivo application. AgNPs were prepared using the citrate reduction method, yielding AgNPs–CTT, which was further chemically conjugated to octreotide (OCT) to form AgNPs–OCT through an amide linkage. The AgNPs–OCT formulation was coated using alginate to yield a carrier, AgNPs–OCT–Alg, feasible for drug delivery through nebulization. AgNPs were uniform in size with an acceptable range of zeta potential. Furthermore, the concentrations of AgNP formulations were found safe for the model cell lines used, and cell proliferation was significantly reduced in a dose-dependent manner (p < 0.05). In the healthy lung tissues, AgNPs–OCT–Alg accumulated at a concentration of 0.416 ± 5.7 mg/kgtissue, as determined via inductively coupled plasma optical emission spectrometry. This study established the accumulation of AgNPs, specifically the AgNPs–OCT–Alg, in lung tissues, and substantiated the active, specific, and selective targeting of SSTRs at pulmonary sites. The anticancer efficacy of the formulations was in vitro tested and confirmed in the MCF-7 cell lines. Owing to the delivery suitability and cytotoxic effects of the AgNPs–OCT–Alg formulation, it is a potential drug delivery formulation for lung cancer therapy in the future.

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Vitamin C Enhances PARPi Efficacy for the Treatment of AML

Blood ◽

10.1182/blood-2021-153884 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 1168-1168

Author(s):

John P Brabson ◽

Tiffany Leesang ◽

Byron Fang ◽

Jingjing Wang ◽

Victoria Strippoli ◽

...

Keyword(s):

Vitamin C ◽

Cell Lines ◽

Combination Treatment ◽

Dna Demethylation ◽

Dependent Manner ◽

Publicly Traded ◽

Colony Forming Capacity ◽

Murine Leukemia

Abstract Poly-ADP-ribose polymerase inhibitors (PARPi) are currently in clinical trial to determine their therapeutic efficacy for the treatment of acute myeloid leukemia (AML). We have shown that vitamin C (VitC), an essential micronutrient and co-factor of Ten-Eleven translocation (TET) proteins, enhances AML sensitivity to PARPi, potentially due to an increased dependency on base-excision repair (BER) enzymes needed to remove TET-catalyzed oxidized methylcytosine bases via active DNA demethylation. TET2 is the most frequently mutated TET gene in patients with AML, and vitamin C treatment can mimic genetic restoration of TET2 function, leading to DNA demethylation, differentiation, and leukemia cell death. Whether vitamin C efficacy in combination with PARPi depends on the level of TET2 functional alleles is not yet known and may stratify whether TET2 wild-type or mutant patients should be targeted by vitamin C adjuvant therapy. We have generated primary murine AML-ETO9a+ and MLL-AF9+ leukemia models with Tet2 +/+, Tet2 +/- and Tet2 -/- alleles to determine the Tet2-dependent efficacy of PARPi treatment when combined with vitamin C. Furthermore, we have performed CRISPR gene knockout and drug library screening in human AML cell lines in combination with vitamin C treatment, and tested a panel of 10 AML cell lines with titrating concentrations of PARPi (Olaparib, Talazoparib, Veliparib and Rucaparib) alone or in combination with vitamin C (L-ascorbic acid) mimicking physiological to pharmacological in vivo doses. Primary murine AML cells and human cell lines were assayed for colony-forming capacity, differentiation, cell cycling, viability and effects on DNA methylation, levels of oxidized 5-mC and gene expression upon combination treatment in vitro and in vivo. TET2 mutant PDX and primary murine AMLs treated in vivo with L-ascorbate (4g/kg) and Olaparib (50mg/kg) by daily IP injection were also monitored for disease burden, cellular differentiation and survival. Vitamin C is known to drive the TET-catalyzed iterative oxidation of 5-methylcytosine (5-mC) leading to the formation of 5-hydroxymethylcytosine (5-hmC), 5-formylcytosine (5-fC) and 5-carboxylcytosine (5-caC). We show that VitC-PARPi combination treatment causes an accumulation of oxidized 5-mC intermediates in the AML genome that correlates with increased yH2AX formation in mid-S phase and cell cycle stalling. Vitamin C reduces the IC 50 of Olaparib and Talazoparib by greater than 10-fold in human AML cells lines and primary murine leukemia cells, and treatment in combination promotes myeloid differentiation and blocks colony-forming capacity greater than either alone. In both our in vitro and in vivo studies, Tet2 +/- AML cells exhibit increased sensitivity to vitamin C treatment alone or in combination with PARPi compared to either Tet2 +/+ or Tet2 -/- cells, suggesting that patients with TET2 haploinsufficiency, which represents the majority of TET2 mutant cases, could benefit the most from combined treatment. Our findings confirm that vitamin C can act synergistically with PARPi to block AML cell viability, reduce colony-forming capacity, and decrease leukemia burden in PDX and primary murine leukemia models in a TET2 allelic dose-dependent manner. The combinatorial effect works at clinically relevant concentrations of PARPi, and low-pharmacological doses of vitamin C. These studies suggest that vitamin C can be used as a non-toxic therapeutic adjuvant to PARPi therapy for the treatment of AML. Disclosures Neel: Northern Biologics, LTD: Current equity holder in publicly-traded company, Other: Co- Founder; SAB: Other: Co-Founder; Navire Pharma: Consultancy, Current equity holder in publicly-traded company; Jengu Therapeutics: Consultancy, Current equity holder in publicly-traded company, Other: Co-Founder; Arvinas, Inc: Consultancy, Current equity holder in publicly-traded company; Recursion Pharma: Current equity holder in publicly-traded company.

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