Cellular Efficacy Research Articles

PEG4000 modified liposomes enhance the solubility of quercetin and improve the liposome functionality: in vitro characterization and the cellular efficacy.

Quercetin, a multifunctional therapeutic agent, is used in various types of cancer. However, its therapeutic effect is limited by virtue of poorly aqueous solubility and instability in the physiological medium. To overcome these limitations, we aimed (i) to design quercetin loaded liposomes with unlinked-PEG4000 with regard to not only surface modification but also solubility enhancement, and (ii) to investigate the antineoplastic effects on HeLa cells. PEG4000 increased the quercetin solubility 2.2 fold. PEG4000 modified liposomes displayed small particle size (254 ± 69 nm), low polydispersity index (0.236 ± 0.018), favorable zeta potential (-35.4 ± 0.6 mV), high quercetin encapsulation efficiency (87.6 ± 5.6%), and drug loading (22.2 ± 6.9%). The homogeneity and particle size of stable PEGylated liposomes were proved by transmission electron microscopy. The drug release was reached up to 65.1 ± 3.8% in 6 h. The IC50 value of quercetin loaded PEGylated liposomes was 16.3 μg/mL on HeLa cells, while that of quercetin was 88.3 μg/mL. PEGylated liposomes remarkably hampered the adherence and colony formation ability of cells according to crystal violet staining tests. The convenience of PEGylated liposomes for the parenteral application was stated by the hemolysis assay. The high-throughput screening assays based on AO/PI staining proved the drastic decrease of viable cell count. Moreover, qPCR tests based on gene expression levels revealed that the quercetin loaded PEGylated liposomes treatment could be more effective than free quercetin on the mitochondrial apoptosis of HeLa cells. These promising results allow considering further in vivo studies for efficient cancer treatment with quercetin loaded PEG4000 modified liposomes.

The druggability of the ATP binding site of glycogen phosphorylase kinase probed by coumarin analogues

Glycogen phosphorylase kinase (PhK) converts by phosphorylation, the inactive glycogen phosphorylase (GPb) into active GPa in the glycogenolytic pathway. It is a complex enzyme comprising of the catalytic (γ) and three regulatory subunits (α, β, δ) forming a hexadecamer with stoichiometry (αβγδ)4. Several studies have indicated PhK as a promising target for the development of antihyperglycemics as its inhibition blocks glycogenolysis in liver and a potential therapeutic target for cancer against pathological angiogenesis and tumor progression. The identification of compounds that inhibit the kinase through their direct binding to its catalytic site is an effective approach to identify bioactive molecules of therapeutic significance. Towards this, the structure of the N-terminal kinase domain (residues 1–298) of the catalytic γ subunit of PhK (PhKγtrnc) has been determined by X-ray crystallography while staurosporine and indirubin analogues have been characterized as potent inhibitors targeting the ATP binding site. In this study, a series of 38 synthetic analogues of naturally occurring coumarins were screened for inhibition of PhKγtrnc, in vitro, using a photometric assay. The IC50 values of the two most potent compounds were determined for PhKγtrnc and the pharmacologically relevant target, human liver isoform (PHKG2A). Their cellular efficacy and toxicity in HepG2 cells were further assessed ex vivo. Docking experiments and the structural comparison with previously described inhibitors reveal the binding mode of the coumarin scaffold at a no hinge region of the ATP site of PhK and the role of a conserved β3-Lys in binding. The experimental findings provide structural insights with implications to the kinase targeting and drug design.

Tumor acidity-responsive polymeric nanoparticles to promote intracellular delivery of zoledronic acid by PEG detachment and positive charge exposure for enhanced antitumor potency.

Zoledronic acid (ZA), a third-generation bisphosphonate, has been extensively used to treat osteoporosis and cancer bone metastasis and demonstrated to suppress proliferation of varied cancer cells and selectively kill tumor-associated microphages (TAMs). However, the clinical applications of ZA in extraskeletal tumor treatment are largely restricted due to its rapid renal clearance and binding to bones. In this study, to promote intracellular delivery of ZA for amplified antitumor efficacy, tumor acidity-responsive polymeric nanoparticles with high ZA payload (ca. 12.3 wt%) and low premature ZA leakage were designed. As a pivotal material for surface coating, the acidity-sensitive and amphiphilic methoxy poly(ethylene glycol) (mPEG)-benzoic imine-octadecane (C18) (mPEG-b-C18) was synthesized by conjugation of mPEG-CHO with 1-octadecylamine upon Schiff base reaction. Through tailor-made co-assembly of the hydrophobic poly(lactic-co-glycolic acid) (PLGA), amphiphilic tocopheryl polyethylene glycol succinate (TPGS) and mPEG-b-C18 to encapsulate ionic complexes composed of ZA molecules and branched poly(ethylenimine) (PEI) segments, the attained therapeutic polymeric nanoparticles, characterized to have a hydrophobic PLGA/ZA/PEI-constituted core covered with mPEG-b-C18 and TPGS, were able to not only detach mPEG shielding upon acidity-triggered hydrolysis of benzoic imine bonds but also expose surface positive charges of protonated PEI segments. The in vitro cellular uptake and cytotoxicity studies demonstrated that the internalization of acidity-sensitive ZA-encapsulated nanoparticles by TRAMP-C1 mouse prostate cancer cells and murine macrophages RAW 264.7 was considerably promoted upon acidity-elicited PEG detachment and surface charge conversion, thus remarkably boosting intracellular ZA delivery and anticancer potency. Compared to PEG non-detachable ZA-loaded nanoparticles with poor tumor deposition and antitumor effect, the PEG-detachable ZA-carrying nanoparticles markedly accumulated in TRAMP-C1 solid tumors in vivo and inhibited tumor growth, thereby increasing the survival rate of the treated mice. The collective data suggest the great promise of tumor acidity-sensitive ZA-carrying hybrid nanoparticles in the treatment of extraskeletal solid tumors.

Study on the Umbilical Cord-Mesenchymal Stem Cell Manufacturing Using Clinical-Grade Culture Medium.

Mesenchymal stem/stromal cell (MSC)-based therapies have been gaining increasing attention owing to their application in various diseases and conditions. In this study, we aimed to identify the optimal condition for industrial-scale MSC manufacturing. MSCs were isolated from umbilical cord (UC) tissues by implementing the explant method (Exp) or a collagenase based-enzymatic digestion method (Col), using a good manufacturing practice-compatible serum-free medium developed in-house. Microarray analysis demonstrated that the gene expression profiles of Exp-MSCs and Col-MSCs did not significantly differ according to the method of isolation or the culture conditions used. The isolated UC-MSCs were then subjected to expansion using conventional static culture (ST) or microcarrier-based culture in stirred-tank bioreactors (MC). Metabolomic and cytokine array analyses were conducted to evaluate the biochemical status of the MSCs. However, no remarkable differences in the metabolic profile and cytokine secretome between ST-MSCs and MC-MSCs were observed. On the contrary, we observed for the first time that the hydrophobic components of ST-MSCs and MC-MSCs were different, which suggested that the cell membrane distribution of fatty acids and lipids was altered in the process of adaptation to shear stress in MC-MSCs. These results establish the flexibility of the isolation and expansion method for UC-MSCs during the manufacturing processes and provide new insights into the minor differences between expansion methods that may exert remarkable effects on MSCs. In conclusion, we demonstrated the feasibility of both Exp-MSCs and Col-MSCs and MC and ST culture methods for scale-up and scale-out of MSC production, as well as the equivalence of these cells. As for the industrialized mass production of MSCs, enzyme-based methods for isolation and cell expansion in a bioreactor were considered to be more suitable. The methods developed, which underwent comprehensive evaluation in this study, may contribute toward the provision of sufficient MSC sources and the establishment of cost-effective MSC therapies. Impact statement Our in-house-developed good manufacturing practice-grade serum-free medium could be used for both isolation (Exp and Col) and expansion (ST and MC) of umbilical cord (UC)-mesenchymal stem/stromal cells (MSCs). Characteristics of the obtained UC-MSCs were widely assessed with regard to gene expression, metabolome, and secretome. Cellular characteristics and efficacy were observed to be equivalently maintained among whichever technique was applied. In addition, our research presents the first evidence that bioreactor and microcarrier-based MSC cultures alter the fatty acid and phospholipid composition of MSCs. These results provide new insights into the differences between expansion methods that may exert remarkable effects on MSCs.

Linking In Vitro Models of Endothelial Dysfunction with Cell Senescence.

Endothelial cell dysfunction is the principal cause of several cardiovascular diseases that are increasing in prevalence, healthcare costs, and mortality. Developing a standardized, representative in vitro model of endothelial cell dysfunction is fundamental to a greater understanding of the pathophysiology, and to aiding the development of novel pharmacological therapies. We subjected human umbilical vein endothelial cells (HUVECs) to different periods of nutrient deprivation or increasing doses of H2O2 to represent starvation or elevated oxidative stress, respectively, to investigate changes in cellular function. Both in vitro cellular models of endothelial cell dysfunction-associated senescence developed in this study, starvation and oxidative stress, were validated by markers of cellular senescence (increase in β-galactosidase activity, and changes in senescence gene markers SIRT1 and P21) and endothelial dysfunction as denoted by reductions in angiogenic and migratory capabilities. HUVECs showed a significant H2O2 concentration-dependent reduction in cell viability (p < 0.0001), and a significant increase in oxidative stress (p < 0.0001). Furthermore, HUVECs subjected to 96 h of starvation, or exposed to concentrations of H2O2 of 400 to 1000 μM resulted in impaired angiogenic and migratory potentials. These models will enable improved physiological studies of endothelial cell dysfunction, and the rapid testing of cellular efficacy and toxicity of future novel therapeutic compounds.

Pirtobrutinib (LOXO-305) Is Active and Overcomes ERK Related Pro-Survival Signaling in Ibrutinib Resistant, BTK Cys481 Mutant Expressing WM and ABC DLBCL Lymphoma Cells Driven By Activating MYD88 Mutations

MYD88 mutations are common in B-cell malignancies including Waldenstrom Macroglobulinemia (WM) and ABC subtype of Diffuse Large B-cell Lymphoma (ABC DLBCL). Mutated MYD88 activates BTK, and triggers downstream pro-survival signaling that includes NF-kB and ERK (Yang et al, Blood 2013; Blood 2016). ERK related signaling triggers inflammatory cytokine production including IL-6 and IL-10 (Chen et al, Blood 2016). Ibrutinib covalently binds to BTK Cys481 and inactivates BTK and downstream NF-kB and ERK signaling. Ibrutinib is approved for the treatment of WM and is associated with high overall response rates (>90%) and long term progression free survival in WM though intolerance to therapy, as well as resistance related to acquired BTK Cys481 mutations frequently leads to treatment discontinuation. We therefore investigated a novel, non-covalent BTK-inhibitor, pirtobrutinib that binds to BTK at non-Cys481 amino acids (G473-K483). Pirtobrutinib showed highly selective anti-proliferative activity against MYD88 mutated WM (BCWM.1, MWCL-1) and ABC DLBCL (TMD-8 and HBL-1) versus MYD88 wild-type (OCI-Ly7, OCI-Ly19, Ramos, and RPMI-8226) cells, with marked apoptotic effect exhibited against primary MYD88 mutated WM cells at pharmacologically achievable levels (100-500 nM). Importantly, pirtobrutinib blocked BTK activity and overcame ibrutinib resistance in BCWM.1 WM and TMD-8 ABC DLBCL cells transduced to express both wild-type and mutated BTK (BTK Cys481Ser) with similar efficacy. The downstream signaling consequences of pirtobrutinib in vector only, wild-type and mutant BTK Cys481 expressing BCWM.1, MWCL-1, TMD-8 and HBL-1 cells was also examined. Treatment of vector only and wild-type BTK Cys481 expressing WM and ABC DLBCL cells with ibrutinib or pirtobrutinib abrogated both p-BTK and p-ERK signaling. In contrast, only pirtobrutinib blocked p-BTK and p-ERK signaling in mutant BTK Cys481 expressing WM and ABC DLBCL cells. In previous studies, we showed that inflammatory cytokine production that included IL-6 and IL-10 driven by ERK triggered ibrutinib resistance in wild-type BTK Cys481 MYD88 mutated lymphoma cells co-cultured with their mutated BTK expressing counterparts (Chen et al, BLOOD 2018). ERK-driven cytokine resistance to ibrutinib was postulated to explain how disease progression occurs in patients with modest variant expression of mutated BTK Cys481 (Woyach et al, JCO 2017; Xu et al, Blood 2017). Co-culture of BTK Cys481 mutated expressing TMD-8 cells with wild-type BTK expressing TMD-8 cells triggered resistance of the latter to ibrutinib. Treatment with pirtobrutinib blocked IL-6 and IL-10 production and overcame the protective effects conferred by BTK Cys481 mutated TMD-8 cells in these experiments. Lastly, oral administration of pirtobrutinib blocked p-BTK and p-ERK in BTK Cys481 mutated TMD-8 tumors xenografted in mice. Our findings therefore show that pirtobrutinib inhibits growth of MYD88 mutated lymphoma cells in a highly selective manner and can trigger apoptosis of primary WM patient BM lymphoplasmacytic cells at levels comparable to ibrutinib. Moreover, pirtobrutinib effectively blocked mutated BTK Cys481 driven BTK and ERK1/2 activation and produced similar cellular efficacy in both BTK wild-type and BTK Cys481 mutated cells. Pirtobrutinib also blocked the protective effect conferred to BTK wild-type cells through paracrine cytokines released by BTK Cys481Ser expressing cells. Lastly, pirtobrutinib blocked BTK and ERK1/2 activation in TMD8-BTK Cys481Ser xenografted mice. The findings support the development of pirtobrutinib in MYD88 driven lymphomas, including those resistant to ibrutinib on the bases of BTK Cys481 mutations. DisclosuresBranagan: Adaptive Biotechnologies: Consultancy; BeiGene: Consultancy; CSL Behring: Consultancy; Karyopharm: Consultancy; Pharmacyclics: Consultancy; Sanofi Genzyme: Consultancy. Castillo: Abbvie: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Janssen: Consultancy; Roche: Consultancy; TG Therapeutics: Research Funding. Yang: Blueprint Medicines Corporations: Current Employment, Current holder of individual stocks in a privately-held company. Treon: BeiGene: Consultancy, Research Funding; Eli Lily: Research Funding; Abbvie/Pharmacyclics: Consultancy, Research Funding.

Silibinin loaded Inhalable Solid lipid Nanoparticles for lung targeting

Aim: In the current study, efforts are being made to prepare Inhalable Silibinin loaded solid lipid nanoparticles (SLNs) with narrow size distribution with improved bioavailability. Methods: SLNs were formulated by high shear homogenization method SLNs were characterized, including Differential Scanning Calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), particle size analysis, entrapment efficiency with Aerodynamic behaviour.. The MTT assay was performed against A549 cell line, to measure their anticancer cell activity with Invio study. Results: Optimized formulation exhibited spherical surface with a mean particle size of 221 ± 1.251 nm, PI of 0.121 ± 0.081, zeta potential of -4.12 ± 0.744. Aerodynamic behaviour such as Mass median aerodynamic diameter (MMAD) and Geometric size distribution (GSD) were found to be 5.487 ± 0.072 and 2.321 ± 0.141 respectively proved formulation is suitable for inhalation. In vitro cellular efficacy against A549 cells, revealed that the optimized formulations were more effective and potent Conclusion: The Inhalable SLNs approach was successfully engineered and administered to the lungs safely without causing any problems.

Heterologous administration of HPV16 E7 epitope-loaded nanocomplexes inhibits tumor growth in mouse model

The nanostructured complexes can result in enhanced vaccine efficacy by facilitating the distribution and uptake of antigens by antigen-presenting cells (APCs), thereby stimulating immune responses. Here, we hypothesized that either directly coating of nanoadjuvants including aluminum phosphate (AlPO4) and adenovirus (Ad) with a modified HPV16 E7 MHC-I specific epitope, RAHYNIVTF49–57, or mixing the CpG oligodeoxynucleotide (CpG-ODN) with the cationic epitope to form nanocomlexes, and their combinational therapy would enhance their anti-tumor effects in a TC-1 mouse model. The positively-charged HPV16 E7 epitope was attracted to the oppositely-charged adjuvants by electrostatic interaction to generate epitope/adjuvant nanocomplexes. We showed that coating the nanosized adjuvants with the cationic epitope increased the particles' surface charge without significant change in their size. We then tested the cellular immunogenicity and therapeutic efficacy of nanocomplexes by measuring IL-10 and IFN-γ production, the expression of CD107a as a marker of CTL response, and tumor growth inhibition. The nanocomplexes were administered either in homologous or heterologous prime-boost regimens, and heterologous immunizations including Ad/Pep-CpG/Pep, CpG/Pep-Ad/Pep, Ad/Pep-Alum/Pep, and Alum/Pep-Ad/Pep induced significantly higher levels of IL-10, IFN-γ, and CD107a-expressing CD8 T cells compared with homologous administrations. Furthermore, the tumor growth was significantly suppressed in mice receiving nanostructured complexes in the heterologous immunizations. Our study highlights the potential of the heterologous prime-boost administration of the epitope-coated nanostructures as an effective immunization strategy.

Design of a "Two-in-One" Mutant-Selective Epidermal Growth Factor Receptor Inhibitor That Spans the Orthosteric and Allosteric Sites.

Inhibitors targeting the epidermal growth factor receptor (EGFR) are an effective therapy for patients with non-small cell lung cancer harboring drug-sensitive activating mutations in the EGFR kinase domain. Drug resistance due to treatment-acquired mutations has motivated the development of successive generations of inhibitors that bind in the ATP site. The third-generation agent osimertinib is now a first-line treatment for this disease. Recently, allosteric inhibitors have been developed to overcome drug-resistant mutations that confer a resistance to osimertinib. Here, we present the structure-guided design and synthesis of a mutant-selective lead compound, which consists of a pyridinyl imidazole-fused benzylisoindolinedione scaffold that simultaneously occupies the orthosteric and allosteric sites. The compound potently inhibits enzymatic activity in L858R/T790M/C797S mutant EGFR (4.9 nM), with a significantly lower activity for wild-type EGFR (47 nM). Additionally, this compound achieves modest cetuximab-independent and mutant-selective cellular efficacies on the L858R (1.2 μM) and L858R/T790M (4.4 μM) variants.

Cellular antioxidant potential and inhibition of foodborne pathogens by a sesquiterpene ilimaquinone in cold storaged ground chicken and under temperature-abuse condition

A sesquiterpene quinone, ilimaquinone, was accessed for its cellular antioxidant efficacy and possible antimicrobial mechanism of action against foodborne pathogens (Staphylococcus aureus and Escherichia coli) in vitro and in vivo. Ilimaquinone was found to be protective against H2O2-induced oxidative stress as validated by the reduction in the ROS levels, including increasing expression of SOD1 and SOD2 enzymes. Furthermore, ilimaquinone evoked MIC against S. aureus and E. coli within the range of 125–250 µg/mL. Ilimaquinone established its antimicrobial mode of action against both tested pathogens as evident by bacterial membrane depolarization, loss of nuclear genetic material, potassium ion, and release of extracellular ATP, as well as compromised membrane permeabilization and cellular component damage. Also, ilimaquinone showed no teratogenic effect against zebrafish, suggesting its nontoxic nature. Moreover, ilimaquinone significantly reduced the S. aureus count without affecting the sensory properties and color values of cold-storaged ground chicken meat even under temperature abuse condition.

Desferrioxamine B-Mediated Pre-Clinical In Vivo Imaging of Infection by the Mold Fungus Aspergillus fumigatus.

Fungal infections are a serious threat, especially for immunocompromised patients. Early and reliable diagnosis is crucial to treat such infections. The bacterially produced siderophore desferrioxamine B (DFO-B) is utilized by a variety of microorganisms for iron acquisition, while mammalian cells lack the uptake of DFO-B chelates. DFO-B is clinically approved for a variety of long-term chelation therapies. Recently, DFO-B-complexed gallium-68 ([68Ga]Ga-DFO-B) was shown to enable molecular imaging of bacterial infections by positron emission tomography (PET). Here, we demonstrate that [68Ga]Ga-DFO-B can also be used for the preclinical molecular imaging of pulmonary infection caused by the fungal pathogen Aspergillus fumigatus in a rat aspergillosis model. Moreover, by combining in vitro uptake studies and the chemical modification of DFO-B, we show that the cellular transport efficacy of ferrioxamine-type siderophores is impacted by the charge of the molecule and, consequently, the environmental pH. The chemical derivatization has potential implications for its diagnostic use and characterizes transport features of ferrioxamine-type siderophores.

Interactions between cells and biomaterials in tissue engineering: a review

Seed cells, biomaterials and growth factors are three important aspects in tissue engineering. Biomaterials mimic extra cellular matrix in vivo, providing a sound environment for cells to grow and attach, so as to maintain cell viability and function. The physicochemical properties and modification molecules of material surface mediate cell behaviors like cell adhesion, proliferation, migration and differentiation, which in turn affect cellular function and tissue regeneration efficacy. Furthermore, the modification molecules of material surface are the direct contact point for cell adhesion and growth. Therefore, the interactions between cells and surface modification molecules are the key to tissue engineering. This review summarizes the effects of surface modification molecules on cell phenotypes and functions.

Development and Characterization of High Efficacy Cell-Penetrating Peptide via Modulation of the Histidine and Arginine Ratio for Gene Therapy.

Cell-penetrating peptides (CPPs), as non-viral gene delivery vectors, are considered with lower immunogenic response, and safer and higher gene capacity than viral systems. In our previous study, a CPP peptide called RALA (arginine rich) presented desirable transfection efficacy and owns a potential clinic use. It is believed that histidine could enhance the endosome escaping ability of CPPs, yet RALA peptide contains only one histidine in each chain. In order to develop novel superior CPPs, by using RALA as a model, we designed a series of peptides named HALA (increased histidine ratio). Both plasmid DNA (pDNA) and siRNA transfection results on three cell lines revealed that the transfection efficacy is better when histidine replacements were on the C-terminal instead of on the N-terminal, and two histidine replacements are superior to three. By investigating the mechanism of endocytosis of the pDNA nanocomplexes, we discovered that there were multiple pathways that led to the process and caveolae played the main role. During the screening, we discovered a novel peptide-HALA2 of high cellular transfection efficacy, which may act as an exciting gene delivery vector for gene therapy. Our findings also bring new insights on the development of novel robust CPPs.

A multiscale approach for bridging the gap between potency, efficacy, and safety of small molecules directed at membrane proteins

Membrane proteins constitute a substantial fraction of the human proteome, thus representing a vast source of therapeutic drug targets. Indeed, newly devised technologies now allow targeting “undruggable” regions of membrane proteins to modulate protein function in the cell. Despite the advances in technology, the rapid translation of basic science discoveries into potential drug candidates targeting transmembrane protein domains remains challenging. We address this issue by harmonizing single molecule-based and ensemble-based atomistic simulations of ligand–membrane interactions with patient-derived induced pluripotent stem cell (iPSC)-based experiments to gain insights into drug delivery, cellular efficacy, and safety of molecules directed at membrane proteins. In this study, we interrogated the pharmacological activation of the cardiac Ca2+ pump (Sarcoplasmic reticulum Ca2+-ATPase, SERCA2a) in human iPSC-derived cardiac cells as a proof-of-concept model. The combined computational-experimental approach serves as a platform to explain the differences in the cell-based activity of candidates with similar functional profiles, thus streamlining the identification of drug-like candidates that directly target SERCA2a activation in human cardiac cells. Systematic cell-based studies further showed that a direct SERCA2a activator does not induce cardiotoxic pro-arrhythmogenic events in human cardiac cells, demonstrating that pharmacological stimulation of SERCA2a activity is a safe therapeutic approach targeting the heart. Overall, this novel multiscale platform encompasses organ-specific drug potency, efficacy, and safety, and opens new avenues to accelerate the bench-to-patient research aimed at designing effective therapies directed at membrane protein domains.

Silencing of HMGA2 by siRNA Loaded Methotrexate Functionalized Polyamidoamine Dendrimer for Human Breast Cancer Cell Therapy.

The transcription factor high mobility group protein A2 (HMGA2) plays an important role in the pathogenesis of some cancers including breast cancer. Polyamidoamine dendrimer generation 4 is a kind of highly branched polymeric nanoparticle with surface charge and highest density peripheral groups that allow ligands or therapeutic agents to attach it, thereby facilitating target delivery. Here, methotrexate (MTX)- modified polyamidoamine dendrimer generation 4 (G4) (G4/MTX) was generated to deliver specific small interface RNA (siRNA) for suppressing HMGA2 expression and the consequent effects on folate receptor (FR) expressing human breast cancer cell lines (MCF-7, MDA-MB-231). We observed that HMGA2 siRNA was electrostatically adsorbed on the surface of the G4/MTX nanocarrier for constructing a G4/MTX-siRNA nano-complex which was verified by changing the final particle size and zeta potential. The release of MTX and siRNA from synthesized nanocomplexes was found in a time- and pH-dependent manner. We know that MTX targets FR. Interestingly, G4/MTX-siRNA demonstrates significant cellular internalization and gene silencing efficacy when compared to the control. Besides, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay demonstrated selective cell cytotoxicity depending on the FR expressing in a dose-dependent manner. The gene silencing and protein downregulation of HMGA2 by G4/MTX-siRNA was observed and could significantly induce cell apoptosis in MCF-7 and MDA-MB-231 cancer cells compared to the control group. Based on the findings, we suggest that the newly developed G4/MTX-siRNA nano-complex may be a promising strategy to increase apoptosis induction through HMGA2 suppression as a therapeutic target in human breast cancer.

Abstract LB136: Targeting GCN2 kinase-driven stress response inactivation by orally available small molecules to restore immune tumor microenvironment in prostate cancers

Abstract In patients with metastatic castration-resistant prostate cancers (mCRPC) who have previously been treated with abiraterone or enzalutamide, the median overall survival is only 14 months. Unlike many other cancers, immunotherapies have had limited successes, due to the fact that there are very few T cells in the tumor microenvironment of prostate cancer (PC) patients. Identifying ways to boost immunotherapy responses could change the paradigm of mCRPC, a disease still difficult to treat. The highly proliferative nature of tumor cells, along with infiltration of myeloid cells into the tumors, leads to depletion of nutrients such as functional/natural amino acids. This metabolically stressful milieu causes activation of nutrient stress pathways, autophagy, and repressed immune responses. A key meditator of this nutrient stress pathway is a cytoplasmic Ser/Thr protein kinase called General Control Nonderepressible 2 (GCN2), also called EIF2AK4. GCN2 switches on by a reduction of amino acids, and its activity results in T cell inactivation, T cell death, regulatory T cell expansion, and the potentiation of myeloid-derived suppressor cells (MDSCs). We have developed and synthesized a series of novel small molecule immunotherapeutic agents that reversibly bind to GCN2 kinase, competitively block the ATP site, and elicit pharmacological responses in immune cells. GCN2 cell-free kinase binding, kinome selectivity, pGCN2, pEIF2α, ATF-4 phosphorylation inhibition assays were performed and confirmed it's on-target efficacy and potency of lead GCN2 inhibitor HCI-1046. In these studies, our lead GCN2 kinase inhibitor HCI-1046 demonstrated potent activity with an IC50 of 36 nM in inhibiting GCN2. GCN2 expression has been detected in PC-3, DU-145, and LNCap cell lines, and HCI-1046 exhibited cellular efficacy with an IC50 of 0.9 to 8 μM range, reduced phosphorylation of GCN2, ATF-4 significantly and its downstream target eIF2α. HCI-1046 inhibited pGCN2 and pEIF2α in human prostate cancer clinical patient samples derived MDSC cultured in amino-acid starved conditions. HCI-1046, in a dose-dependent fashion, restored CD8+ T cell proliferation and function in clinical samples of PC patients. Our preliminary results support the hypothesis that inhibition of GCN2 reinstates anti-tumor immunity and blocks tumor progression in PC cellular models. In vivo PK studies of HCI-1046 in rodent species showed excellent PK properties; 55% oral bioavailability, low clearance, and &amp;gt;5 hours half-life. HCI-1046 is nominated as a pre-clinical agent. Additional 3D cellular efficacy studies, FACS for cellular apoptosis, cell migration, live PC cells including immuno-ELISA, ELISpot experimental results for MDSCs suppressive function of T cells, and restoration by HCI-1046 will be presented at the conference. PC mouse model efficacy studies will also be discussed. Citation Format: Kyle Medley, Zhaoliang Li, Dongqing Yan, Umang Swami, Neeraj Agarwal, Hariprasad Vankayalapati. Targeting GCN2 kinase-driven stress response inactivation by orally available small molecules to restore immune tumor microenvironment in prostate cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB136.

Abstract 1019: The MET inhibitor tepotinib shows sustained effects on MET phosphorylation and viability in cellular washout experiments

Abstract It is well accepted that a drug's efficacy is modulated by the affinity of the drug to the target of interest and the stability of the protein/inhibitor complex. Additionally, drug efficacy is affected by pharmacokinetic properties. For example, lipophilic weak bases are able to easily permeate membranes at neutral pH in a non-protonated form, but also tend to accumulate in acidic compartments such as lysosomes. Consequently, lysosomes can act as a drug reservoir. The degree of lysosomal sequestration generally correlates with the pKa value of the basic function, and although the process is considered to be fully reversible, the degree and accessibility of the lysosomal reservoir heavily depends on compound-specific physicochemical properties. MET inhibitors such as crizotinib, capmatinib, savolitinib and tepotinib are providing the opportunity to study how differences in the physicochemical profiles of MET inhibitors affect the interplay of drug-target residence time and lysosomal storage, and how these factors translate into target inhibition and cell viability effects under washout conditions. Human lung cancer cell lines were treated with MET inhibitors across a range of concentrations for 1 h, cells were washed to remove compounds in the supernatant, and remaining compound activity was analyzed by measuring MET phosphorylation and lung cancer cell viability. Tepotinib showed persistent effects in both assays with significant differences observed between the tested MET inhibitors. In the viability assay comparing standard and washout conditions, the half-maximal inhibitory concentrations of tepotinib and crizotinib increased by a factor ranging from 10 to 20. In contrast, those of capmatinib and savolitinib increased by a factor &amp;gt;250, indicating a more sustained efficacy for tepotinib and crizotinib under washout conditions. Here, we present data on the underlying mechanisms affecting cellular efficacy under washout conditions, including residence time via surface plasmon resonance analysis, compound-partition coefficients via liquid chromatography with tandem mass spectrometry quantification, and lysosomal storage via a competitive dye displacement assay. This comparative analysis provides strong evidence that tepotinib demonstrates persistent efficacy in dynamic cellular systems, exceeding that of several other MET inhibitors. The underlying reason for this observation is probably the consequence of a long residence time of tepotinib (~20 h) combined with an optimal physicochemical profile allowing for a beneficial contribution of lysosomal retention. These in vitro findings may also explain the sustained pharmacokinetic and pharmacodynamic in vivo characteristics of tepotinib. Citation Format: Nina Berges, Jan Henrik Klug, Anna Eicher, Jennifer Loehr, Daniel Schwarz, Joerg Bomke, Birgitta Leuthner, Dominique Perrin, Oliver Schadt. The MET inhibitor tepotinib shows sustained effects on MET phosphorylation and viability in cellular washout experiments [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1019.

Impact of Humoral Immunogenicity (Anti-mCAR19 Antibodies) on CTL019 Cellular Kinetics, Efficacy, and Safety

Background: The humoral immunogenicity of CAR19, a chimeric antigen receptor with a murine scFV domain developed for treatment with CTL019 (tisagenlecleucel) in relapsed/refractory (R/R) pediatric and young adult acute lymphoblastic leukemia (ALL), was evaluated in 2 studies (ELIANA [NCT02435849]; ENSIGN [NCT02228096]). To date, little is known about the presence and impact of preexisting or treatment-induced anti-murine (m)CAR19 antibodies in patients treated with CAR T-cell therapy.Methods: Anti-mCAR19 antibodies were measured in patients from ELIANA and ENSIGN trials before and after CTL019 infusion to evaluate the impact of anti-mCAR19 antibodies on cellular kinetics, efficacy, and safety. Data were pooled from ELIANA (n = 68) and ENSIGN (n = 29). Anti-mCAR19 antibodies were captured by mCAR19-transfected Jurkat cells and wild-type Jurkat cells. Following incubation and washing, an R-phycoerythrin (PE)-labeled anti-IgG/M F(ab')2 fragment was added for detection of anti-mCAR19 antibodies using flow cytometry and reported as median fluorescence intensity (MFI). Exploratory assay development included assessment of whether the presence of immunoglobulins after IVIG therapy in clinical samples would interfere with the anti-mCAR19 antibody assay. Impact of preexisting immunogenicity, as detected by MFI levels, was evaluated using cellular kinetic, efficacy, and safety endpoints. The impact of treatment-induced immunogenicity (defined as having an increase in anti-mCAR19 antibody levels over baseline) was assessed by calculating the fold change between preexisting (ie, baseline) levels and postinfusion levels.Results: Approximately 90% of patients displayed preexisting anti-mCAR19 antibodies; a similar incidence was detected in healthy volunteer samples, as observed during assay development. Approximately 35% of patients developed treatment-induced anti-mCAR19 antibodies. No apparent relationship between CTL019 expansion (AUC0-28d) and preexisting or treatment-induced anti-mCAR19 antibodies was identified (r2 < 0.001 and r2 = 0.006, respectively); similar results were seen for Cmax (Figure 1a). Presence of anti-mCAR19 after infusion did not appear to influence the persistence of transgene or day 28 response (Figure 1b). Kaplan-Meier curves showed that the presence of preexisting and treatment-induced anti-mCAR19 antibodies did not appear to impact the duration of response or event-free survival (Figure 1c). Strip plots showed consistent levels of preexisting and treatment-induced anti-mCAR19 antibodies across patients with safety events (grade 0/1/2/3/4), including CRS, neutropenia, thrombocytopenia, and neurological events. There was no apparent relationship between treatment- induced anti-mCAR19 antibodies with B-cell recovery categories (recovery ≤ 3 months, > 3 months and ≤ 6 months, > 6 months, and ongoing sustained B-cell aplasia). There was also no association in patients at the time of B-cell recovery with the presence of treatment-induced anti-mCAR19 antibodies following CTL019 infusion. B-cell aplasia requiring immunoglobulin replacement therapy (IVIG) occurred following CTL019 in the majority of patients. The CTL019 concentration time profiles for patients with treatment-induced anti-mCAR19 antibodies were categorized by the time following IVIG administration (within 1 week, 2 weeks, or > 3 weeks of IVIG administration). The results revealed no impact of the time at which IVIG was administered on the in vivo expansion and persistence of the transgene.Conclusions: We report the first comprehensive assessment of the impact of anti-mCAR antibodies on clinically relevant endpoints for CAR therapy. Determination of immunogenicity is an important endpoint required by health authorities for biologic drugs, and these analyses demonstrate the importance of characterizing the impact on clinical endpoints for CAR therapies. These analyses in patients with pediatric R/R ALL revealed a surprisingly high frequency of baseline anti-mCAR19 antibodies and showed that the presence of preexisting and treatment-induced anti-mCAR19 antibodies did not impact the cellular kinetics, safety, and efficacy of CTL019. Cell-mediated immunity studies are ongoing. [Display omitted] DisclosuresMueller:Novartis Pharmaceuticals Corporation: Employment. Waldron:Novartis Pharmaceuticals Corporation: Employment. Sickert:Novartis Institutes for BioMedical Research: Employment. Grupp:University of Pennsylvania: Patents & Royalties; Novartis Pharmaceuticals Corporation: Consultancy, Other: grant; Adaptimmune: Consultancy; Jazz Pharmaceuticals: Consultancy. Maude:Novartis Pharmaceuticals: Consultancy, Other: Medical Advisory Boards. Levine:Novartis Pharmaceuticals Corporation: Membership on an entity's Board of Directors or advisory committees. Laetsch:Novartis Pharmaceuticals Corporation: Consultancy. Pulsipher:Novartis Pharmaceuticals Corporation: Consultancy, Other: Phase II steering committee; Chimerix: Other: Advisory board Dec 2015; Jazz Pharmaceuticals: Other: advisory board, education; CSL Behring: Other: advisory board Feb 2017; Adaptive: Other: Advisory board 6/17. Boyer:Novartis Pharmaceuticals Corporation: Honoraria. August:Novartis Pharmaceuticals Corporation: Consultancy. Awasthi:Novartis Pharmaceuticals Corporation: Employment. Levine:GE Healthcare: Consultancy; Novartis Pharmaceuticals Corporation: Patents & Royalties, Research Funding; Brammer Bio: Consultancy; Tmunity Therapeutics: Equity Ownership, Research Funding. June:WIRB/Copernicus Group: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celldex: Honoraria, Membership on an entity's Board of Directors or advisory committees; Immune Design: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Novartis: Patents & Royalties, Research Funding; Tmunity Therapeutics: Equity Ownership, Research Funding. Taran:Novartis Pharmaceuticals Corporation: Employment, Equity Ownership. Wood:Novartis Pharmaceuticals Corporation: Employment, Equity Ownership. Myers:Novartis Pharmaceuticals Corporation: Consultancy.

Charting Venetoclax Sensitivity and Synergism Ex Vivo in Multiple Myeloma

We have implemented a drug screening platform for evaluation of multiple myeloma (MM) relevant therapeutics alone or in combination, providing immediate actionable results. We assembled 80 assay-ready, MM relevant FDA approved drugs and clinical trial therapeutics. This panel was evaluated in 25 MM and 10 Non-Hodgkin lymphoma cell lines, and in 65 primary MM samples using a viability endpoint. The panel includes venetoclax, a selective BCL-2 inhibitor that is currently in clinical development for MM as a single agent or in combination with bortezomib and dexamethasone. Single agent clinical trial results have shown that venetoclax is active in 21% of all relapsed refractory MM patients, 40% of patients with a t(11;14) and only 9% of patients lacking this translocation. It is unclear why not all patients with this translocation respond and who the 9% of non-translocated responders are. We were interested to know if our assay exhibited the same targeted pattern of activity and in assembling a genomic database to interrogate these questions.The cellular efficacies of the MM drug panel, including venetoclax, were measured using the CellTiter Glo assay (Promega), in 25 MM cell lines using 7 drug doses covering a broad concentration range at both 24 and 72 hour time points. Concurrent with clinical observations, venetoclax presents a differential activity profile (Table 1). At 72h drug incubation, 75% of t(11;14) MM cell lines responded with an EC50<100nM but only 3 of 21 (14%) of translocation negative cell lines responded (overall response rate of 24%). Ex vivo sensitivity to venetoclax was also measured following 24h drug exposure in CD138+ selected tumor cells from 56 MM patients, 15 of which have a t(11;14). A majority of patient samples (85%) exhibit a dose response curve to venetoclax, but a broad EC50 range is observed (0.59 to 4900 nM). Twenty-seven patient samples (48% of all those tested) were inhibited by venetoclax at <100 nM concentrations, 10 of the 15 patients with t(11;14) responded at <100 nanomolar EC50, accounting for 67% of the samples with that translocation. Two patients with a t(6;14) also responded. For patients who lack either cyclin D1/D3 translocations (n=39), 15 responded with efficacies <100nM, or 38%. These trends are confirmed by median efficacies, with a median EC50 for t(11;14) samples of 29nM, much lower than the 118nM median observed for samples without this translocation. Nevertheless 17 of 41 patients lacking the t(11;14) are sensitive below 100nM EC50, a group which clearly deserves a deeper genomic analysis and clinical correlation.Using venetoclax as a base drug, we then studied all possible combinations with the 79 other agents of the MM drug panel in sensitive and resistant HMCLs. The cytotoxic response of the base and combined drugs was measured in 5-point 2-fold drug dilutions centered on their respective EC50s. Primary combination screen results were scored using consensus performance metrics from Chou-Talalay, Highest Single Agent (HSA), and Bliss independence models. Combinations predicted synergistic by at least 2 methods were confirmed in a matrix format. The screen combining venetoclax and the drug panel was designed to identify synergistic combinations that enhance venetoclax response in groups that lack t(11;14) and have either intermediate sensitivity (OPM2) or are resistant (AMO1). In OPM2, 25 drugs were found to synergize with venetoclax with a combination index CI < 0.2 (strong synergism), vs 1 non overlapping drug in the resistant HMCL, AMO1. The confirmation of these findings in a matrix format and in sensitive cell lines will be reported.In summary, our data corroborates the clinical observation of a strong pattern for venetoclax response and t(11;14) through drug screening in primary patient materials ex vivo with a 24 hour read out. Using this strategy we will begin to add drug combinations of high promise to our drug screening platform to develop the map of drug synergism in multiple myeloma.Acknowledgments: We thank the Multiple Myeloma Research Foundation for funding this project. [Display omitted] DisclosuresStewart:Bristol-Myers Squibb: Consultancy; Janssen: Consultancy; Amgen: Consultancy; Celgene: Consultancy; Roche: Consultancy.

PIKfyve Inhibitors for the Treatment of Multiple Myeloma

IntroductionUsing a high throughput screening approach employing ~80 FDA approved, late stage clinical trial, or drugs of interest to multiple myeloma (MM), we examined single agent drug sensitivity of 35 MM and lymphoma cell lines and in 65 primary MM samples. We identified APY-0201, a PIKfyve inhibitor (P5I), as lethal at nanomolar concentrations in 48% of human myeloma cell lines (HMCLs) and 28.6% of primary MM samples after 24 hour of drug exposure. In 20% of patient samples, in vitro sensitivity was less than 100nM EC50. PIKfyve is a lipid and protein kinase that controls pleiotropic cellular functions, notably regulation of endomembrane homeostasis; mechanisms of sensitivity and resistance were explored.MethodsApilimod, a key P5I initially developed as an interleukin (IL)-12 and IL-23 inhibitor, has been used as an immunomodulatory agent in the treatment of inflammatory diseases and has been recently suggested for the treatment of neoplastic diseases, including B-cell Non-Hodgkin's Lymphoma (NHL). YM201636 has also been described as a potent P5I. The cellular efficacies of APY-0201, apilimod, and YM201636 in HMCLs were assessed using the CellTiter Glo assay (Promega), in 20-point 2-fold dilutions of drug concentrations at 72 hours; and HMCL P5I sensitivity was correlated with RNA-SEQ data publically available at www.keatslab.org. Cell lysates were extracted for western blot expression analysis of transcription factor EB (TFEB), cathepsin D, caspase 3, poly (ADP-ribose) polymerase (PARP), at different drug exposure time points (3, 6, 12, 24, 48, and 72 hours). Ex vivo sensitivity to APY-0201, the most potent studied P5I, was measured in CD138+ primary cells of 56 primary MM patients at 24 hours. In vivo activity of apilimod at 100-150 mg/kg and APY-0201 at 30-45 mg/kg was evaluated over 2 weeks in the Vk*MYC transgenic mouse model of MM. Tumor burden was measured by weekly evaluation of M-spike serum levels.ResultsAPY-0201 was the most potent P5I, followed by YM201636 and apilimod. However, dose-dependent inhibition of cell viability was observed in all HMCLs. APY-0201 EC50 ranged from 2.8 to 266.7nM (mean 123.4nM), 63.8 to 8425.8nM (mean 1329nM) for YM201636, and 62.5 to 3561.2nM (mean 2026nM) for apilimod. APY-0201 maximum inhibition ranged from 68.2 to 100% (mean 87.2%), 33.2 to 100% (mean 64.6%) for YM201636, and 56.7 to 100% (mean 83.6%) for apilimod. A significant correlation between low RNA-SEQ expression of TFEB, which regulates lysosomal biogenesis and autophagy, and lower sensitivity for APY-0201 was found (Wilcoxon signed-rank test p-value = 0.017). No correlation with baseline OSTM1, CLCN7 or SNX10 levels was seen.APY-0201 dose dependent sensitivities were observed in 37.5% of ex vivo patient samples. Of the 21 patients demonstrating sensitivity, 2 were inhibited at an EC50<10nM (median 8.58nM), 10 samples presented EC50 between 10 and 100nM (median 64.67nM), and 9 samples presented EC50>100nM (median 1000.16nM). Thus, 12 (21.4%) primary MM patient samples exhibited lethality with less than 100nM concentration of APY-0201 after 24 hours. P5I activity profile was not obviously correlated with clinical findings, such as stage of disease or genetic subtype, in either cell lines or primary samples.As demonstrated previously in B-cell NHL, treatment of the most sensitive cell line, KMS26, with apilimod and APY-0201 was associated with activation of TFEB, found in its dephosphorylated state. An accumulation of the inactive precursor procathepsin D was also observed in KMS26 following treatment, demonstrating a decrease in maturation of lysosomal proteases. Furthermore, the cytotoxic activity of both compounds was shown by induction of apoptosis makers, i.e. caspase 3 and PARP. In ongoing studies, in vivo activity was evident in 2 of 6 Vk*MYC transgenic MM mice treated with a P5I; dose finding and longer treatment duration studies are underway.ConclusionsInhibition of PIKfyve surprisingly demonstrated promising anti-myeloma activity in vitro, ex vivo and in vivo, thus providing a rationale for further evaluation in the treatment of MM. As reported by others in NHL, a novel mechanism of action involving disruption of endolysosomal function is suggested in PIKfyve mediated cytotoxicity in MM.AcknowledgmentThis work was supported in part by the Multiple Myeloma Research Foundation. DisclosuresSharik:Phosplatin Therapeutics: Research Funding. Sepetov:Nanosyn Inc.: Employment. Romanov:Nanosyn Inc.: Employment. Bergsagel:Phosplatin Therapeutics: Research Funding. Chesi:Phosplatin Therapeutics: Research Funding. Stewart:Amgen: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Roche: Consultancy.