MTS Proliferation Assay Research Articles

Abstract 448: Alterations in glycolytic pathway enzymes and metabolic plasticity in prostate cancer progression

Abstract Background: Although oxidative phosphorylation (OXPHOS) is the main ATP source in primary prostate cancer, as the tumor progresses to castration resistance and/or metastatic disease, glycolysis becomes increasingly prevalent. Dependence on glycolysis can further increase under hypoxic conditions found in advanced cancers. We previously demonstrated that a novel small molecule, BKIDC-1553, inhibits proliferation and tumor growth of prostate cancer cell lines and xenografts through a hexokinase-2 (HK2) dependent inhibition of glycolysis. HK2 is a glucose 6-phosphorylating enzyme that works in conjunction with glucose transporter-1 (GLUT1) to drive glycolysis in cells. While our previous work suggests that BKIDC-1553 works primarily through a HK2 dependent mechanism, the objective of this current project is to further examine how expression and function of HK2 and GLUT1 are altered in response to BKIDC-1553 treatment. Methods: Hypoxic conditions are common in late-stage prostate cancer. Effects of hypoxia on cell proliferation and expression levels of HK1, HK2, and GLUT1 were examined with and without BKIDC-1553 treatment. To examine role of HK1, HK2, and GLUT1 in response to BKIDC-1553 treatment, we created CRISPR knockouts and shRNA knockdowns of HK1 and HK2 in the LNCaP prostate cancer cell line. GLUT1 was inhibited using a commercially available inhibitor, BAY-876. PCR and Western blots were used to confirm expression levels of HK1, HK2, and GLUT1. MTS proliferation assays were used to examine effect of KO and KD on response to BKIDC-1553 and BAY-876. Results: GLUT1 levels, but not HK1 or 2, increased at 72 hrs under hypoxic conditions. HK1, HK2, and GLUT1 levels all increased in cells in response to 144 hrs of BKIDC-1553 compared with 72 hrs treatment in both normoxic and hypoxic conditions. The KO and KD studies were all conducted in normoxic conditions. Westerns blots demonstrated that HK2 KO, but not HK1 KO, results in increased levels of GLUT1. HK1 or HK2 KD, however, did not alter GLUT1 levels. HK2 KD cells, with GLUT1 levels remaining the same, displayed less growth inhibition than control cells in response to BKIDC-1553 treatment, while HK2 KO cells, with increased levels of GLUT1, remained sensitive to BKIDC-1553. Because GLUT1 levels increase in response to HK2 KO, we wanted to see if inhibiting GLUT1 in these cells could decrease their proliferation. We found that KO cells were indeed more sensitive to growth inhibition of BAY-876. Conclusion/Summary: These studies indicate that KO of HK2 increases levels of GLUT1. These cells remain sensitive to BKIDC-1553 treatment, which could in part be due to the cells' continued reliance on glycolysis through increased GLUT1. A continued reliance on glycolysis allows BKIDC-1553 to continue to inhibit cell growth. Future studies examining how combination treatment with BKIDC-1553 and BAY-876 affects growth of advanced prostate cancer cells is underway. Citation Format: Cynthia Sprenger, Mika Munari, Shihua Sun, Kathryn Soriano Epilepsia, Stephen Plymate. Alterations in glycolytic pathway enzymes and metabolic plasticity in prostate cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 448.

Abstract 3204: Antitumor activity of a coencapsulated liposomal formulation of ceramides and doxorubicin in neuroblastoma models

Abstract Background: Neuroblastoma (NB) represents the most frequent and aggressive form of extracranial solid tumor of infants. Targeted therapies are severely limited by the lack of specific receptors, thus chemotherapy and radiotherapy remain the main treatment choices, which expose NB patients to systemic toxicity. Recently, we have demonstrated that cell surface Nucleolin (NCL) represents a novel cellular target for NB therapy. Methods: The cytotoxic potential of pH-sensitive nanocarriers (NC), decorated with the NCL-recognizing F3 peptide and incorporating a combination of the PI3K/Akt signaling inhibitors, C6-Ceramide (C6-Cer) or C18-ceramide (C18-Cer), and the topoisomerase II inhibitor doxorubicin (DXR) (F3-NC[C6-Cer/DXR] and F3-NC[C18-Cer/DXR], respectively), was tested in vitro on a panel of NB cell lines. Cytotoxicity was evaluated in monolayer and in multicellular tumor spheroid models, by MTS proliferation and Cell Titer Glo 3D cell viability assays, respectively. Apoptotic/necrotic cell death was investigated by Real Time-Glo Annexin VApoptosis and Necrosis assay. Results: F3-NC[C6-Cer/DXR] and F3-NC[C18-Cer/DXR] resulted significantly more effective, in term of reduction of NB cell viability, compared to the corresponding “drugs”-loaded untargeted NC formulations. Both formulations triggered apoptotic cell death, even if in a different kinetic profile. In particular, NB cells treated with F3-NC[C6-Cer/DXR] underwent apoptotic cell death earlier with respect to those treated with F3-NC[C18-Cer/DXR]. Interestingly, F3-NC[C6-Cer/DXR] exerted a significant superior cell killing effect when compared both to F3-NC[C18-Cer/DXR] and to F3-NC encapsulating only DXR, suggesting the importance of the combination treatment to enhance the antitumor effect against NB cells. Conclusion: Our preliminary findings demonstrate that the co-encapsulation and delivery of C6-Ceramide and DXR by NCL-recognizing nanoparticles exert potent antitumor effects against NB models in vitro. Ongoing in vivo experiments on clinically relevant mouse NB models (i.e. recapitulating primary tumor growth, metastases, and minimal residual disease) will allow us to define the possible use of F3-NC[C6-Cer/DXR] as an innovative therapeutic strategy for relapsed/refractory NB. Funding: AIRC IG n. 24397 to PF; CInTech (PRR) C644865576-00000005 to JNM.VB is recipient of AIRC ID 24397 contract. MBC is recipient of PD/BDE/150664/2020 (FCT) fellowship. Citation Format: Veronica Bensa, Mariana Biscaia-Caleiras, Mirco Ponzoni, Joao Nuno Moreira, Chiara Brignole, Fabio Pastorino. Antitumor activity of a coencapsulated liposomal formulation of ceramides and doxorubicin in neuroblastoma models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3204.

Synthesis and Preliminary Evaluation of an ASGPr-Targeted Polycationic β-Cyclodextrin Carrier for Nucleosides and Nucleotides.

Most antiviral and anticancer nucleosides are prodrugs that require stepwise phosphorylation to their triphosphate nucleotide form for biological activity. Monophosphorylation may be rate-limiting, and the nucleotides may be unstable and poorly internalized by target cells. Effective targeting and delivery systems for nucleoside drugs, including oligonucleotides used in molecular therapeutics, could augment their efficacy. The development of a carrier designed to effect selective transmembrane internalization of nucleotides via the asialoglycoprotein receptor (ASGPr) is now reported. In this work, the polycationic, polygalactosyl drug delivery carrier heptakis[6-amino-6-deoxy-2-O-(3-(1-thio-β-D-galactopyranosyl)-propyl)]-β-cyclodextrin hepta-acetate salt (GCyDAc), potentially a bifunctional carrier of (poly)nucleotides, was modeled by molecular docking in silico as an ASGPr-ligand, then synthesized for testing. The antivirals arabinosyl adenine (araA, vidarabine, an early generation antiviral nucleoside), arabinosyl adenine 5'-monophosphate (araAMP), and 12-mer-araAMP (p-araAMP) were selected for individual formulation with GCyDAc to develop this concept. Experimentally, beta cyclodextrin was decorated with seven protonated amino substituents on the primary face, and seven thiogalactose residues on its secondary face. AraA, araAMP, and p-araAMP were individually complexed with GCyDAc and complex formation for each drug was confirmed by differential scanning calorimetry (DSC). Finally, the free drugs and their GCyDAc complexes were evaluated for antiviral activity using ASGPr-expressing HepAD38 cells in cell culture. In this model, araA, araAMP, and p-araAMP showed relative antiviral potencies of 1.0, 1.1, and 1.2, respectively. In comparison, GCyDAc-complexes of araA, araAMP, and p-araAMP were 2.5, 1.3, and 1.2 times more effective than non-complexed araA in suppressing viral DNA production. The antiviral potencies of these complexes were minimally supportive of the hypothesis that ASGPr-targeted, CyD-based charge-association complexation of nucleosides and nucleotides could effectively enhance antiviral efficacy. GCyDAc was non-toxic to mammalian cells in cell culture, as determined using the MTS proliferation assay.

Alginate Beads as a Promising Tool for Successful Production of Viable and Pluripotent Human-Induced Pluripotent Stem Cells in a 3D Culture System.

Two-dimensional (2D)-based cell culture systems, limited by their inherent heterogeneity and scalability, are a bottleneck in the production of high-quality cells for downstream biomedical applications. Finding the optimal conditions for large-scale stem cell culture while maintaining good cellular status is challenging. The aim of this study was to assess the effects of three-dimensional (3D) culture on the viability, proliferation, self-renewal, and differentiation of human induced pluripotent stem cells (IPSCs). Various culture conditions were evaluated to determine the optimal conditions to maintain the viability and proliferation of human IPSCs in a 3D environment: static versus dynamic culture, type of adhesion protein added to alginate (Matrigel™ versus gelatin), and the addition of Y-27632t on long-term 3D culture. The proliferation ability of the cells was evaluated via the MTS proliferation assay; the expression levels of the pluripotency markers Nanog and Oct3/4, PAX6 as an ectoderm marker, and laminin-5 and fibronectin as markers of extracellular matrix synthesis were assessed; and HIF1α and HIF2α levels were measured using quantitative reverse transcription polymerase chain reaction. Using a high-aspect-ratio vessel bioreactor with a gentle, low-sheer, and low-turbulence environment with sufficient oxygenation and effective mass transfer of nutrients and waste, we verified its ability to promote cell proliferation and self-renewal. The findings showed that human IPSCs have the ability to maintain pluripotency in a feeder-free system and by inhibiting ROCK signaling and using hypoxia to improve single-cell viability in 3D culture. Furthermore, these cells demonstrated increased self-renewal and proliferation when inoculated as single cells in 3D alginate beads by adding RI during the culture period. Dynamic 3D culture is desirable for the large-scale expansion of undifferentiated human IPSCs.

Metformin Induces a Caspase 3-Unrelated Apoptosis in Human Colorectal Cancer Cell Lines HCT116 and SW620.

To study the effects of metformin on the proliferation and growth of human colorectal cancer cell lines HCT116 and SW620. The antiproliferative effect of metformin was assayed using an MTS reagent and its ability to inhibit colony formation was demonstrated using a clonogenic assay. Flow cytometry using YO-PRO-1/PI was performed to examine the effects of metformin on apoptosis and cell death of HCT116 and SW620. Caspase 3 activities were measured in caspase-3 activity tests using a caspase-3 activity kit. Furthermore, Western blots were performed with anti-PARP1, anti-caspase 3, and anti-cleaved caspase 3 to confirm whether caspase activation was present or not. Both MTS proliferation assays and clonogenic assays showed that metformin inhibited the proliferation and growth of HCT116 and SW620 cells in a concentration-dependent manner. Flow cytometric analysis identified early apoptosis and metformin-induced cell death in both cell lines. However, caspase 3 activity could not be detected. Cleavage of both PARP1 and pro-caspase 3 was not observed in the Western blot, confirming the absence of caspase 3 activations. This present study suggests a caspase 3-unrelated apoptosis mechanism of metformin-induced cell death in human colorectal cancer cell lines HCT116 and SW620.

Abstract PR011: DCIS-associated myoepithelial cells drive tumor progressive inflammation through up-regulation of integrin αvβ6

Abstract Background: Ductal carcinoma in-situ (DCIS) is a pre-invasive stage of breast cancer, however <50% will progress to invasion. A key component in promoting tumor invasion is inflammation, though its role in DCIS progression is unclear. We previously, showed αvβ6 expression on DCIS myoepithelial cells promotes tumor cell invasion. We hypothesized that altered myoepithelial phenotype in DCIS may modulate periductal inflammation to contribute to disease progression. Methods: The inflammatory infiltrate in DCIS cases (20 αvβ6+ and 20 αvβ6-) was characterized by immunohistochemistry (IHC) and immunofluorescence-IHC, focusing on Tumor Associated Macrophages (TAM) and Regulatory T cell markers. A myoepithelial cell line over-expressing αvβ6 (β6-1089) and a control counterpart (N-1089) were analyzed for cytokine and signaling molecule expression with proteome profilers and western blotting. The monocyte cell line (THP-1) was exposed to conditioned media from β6-1089 or N-1089 followed by qPCR for TAM markers (IL4, IL10 and IL8), MTS proliferation assay and western blotting for NFkB and STAT6 activation (involved in macrophage differentiation). 3D models were used to examine if the in vivo changes to macrophages can be modelled in vitro. Results: IHC analysis revealed a significant association between myoepithelial αvβ6 expression and increased T-reg cell infiltrate (p< 0.0001). Similarly, αvβ6 expression associated with increased presence of TAM (p=0.0026), αvβ6 positive DCIS with exhibited a microenvironment comprising 15% TAMs compared to 3% in αvβ6 negative DCIS cases. This shift in macrophage phenotype was recapitulated in 3D organotypic assays incorporating macrophages and myoepithelial cells. Proteome profiler analysis of THP-1 cells grown with conditioned media from αvβ6 positive myoepithelial cells demonstrated increased expression of CCL5 while all other proteins analyzed where generally suppressed. Nuclear and cytoplasmic western blotting of THP-1s demonstrated NfκB and STAT activation were altered by CM from myoepithelial cells +/- avb6. Conclusion: DCIS myoepithelial cells upregulate αvβ6 and exhibit changes in the periductal inflammatory infiltrate indicating a switch to a tumor promoting phenotype. Further investigation is required to determine the prognostic value and underlying mechanisms of this change. Citation Format: Michael D. Allen, M. Reza Roozitalab, Stephen Murtough, Eleni Maniati, J. Louise Jones. DCIS-associated myoepithelial cells drive tumor progressive inflammation through up-regulation of integrin αvβ6 [abstract]. In: Proceedings of the AACR Special Conference on Rethinking DCIS: An Opportunity for Prevention?; 2022 Sep 8-11; Philadelphia, PA. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_1): Abstract nr PR011.

Gelatin-Based Hybrid Hydrogel Scaffolds: Toward Physicochemical Liver Mimicry.

There exists a clear need to develop novel materials that could serve liver tissue engineering purposes. Those materials need to be researched for the development of bioengineered liver tissue as an alternative to donor livers, as well as for materials that could be applied for scaffolds to develop an in vitro model for drug-induced liver injury (DILI) detection . In this paper, the hydrogels oxidized dextran-gelatin (Dexox-Gel) and norbornene-modified dextran-thiolated gelatin (DexNB-GelSH) were developed, and their feasibility toward processing via indirect 3D-printing was investigated with the aim to develop hydrogel scaffolds that physicochemically mimic native liver tissue. Furthermore, their in vitro biocompatibility was assessed using preliminary biological tests using HepG2 cells. Both materials were thoroughly physicochemically characterized and benchmarked to the methacrylated gelatin (GelMA) reference material. Due to inferior properties, Dexox-gel was not further processed into 3D-hydrogel scaffolds. This research revealed that DexNB-GelSH exhibited physicochemical properties that were in excellent agreement with the properties of natural liver tissue in contrast to GelMA. In combination with an equally good biological evaluation of DexNB-GelSH in comparison with GelMA based on an MTS proliferation assay and an albumin quantification assay, DexNB-GelSH can be considered promising in the field of liver tissue engineering.

A Novel Spirocyclic Dimer (36-286) Targeting the NF-Kappa B Pathway Displays Potent Anti-Tumor Properties in Chronic Lymphocytic Leukemia

Introduction: Chronic lymphocytic leukemia (CLL) is an incurable, heterogenetic disease dependent on B cell receptor (BCR) signaling with subsequent nuclear factor-kappa B (NF-κB) activation resulting in the evasion of apoptosis and enhanced malignant B cell growth. Targeted therapies such as ibrutinib (IBR; BTK inhibitor) and venetoclax (VEN; BCL2 antagonist) have revolutionized the management of CLL, however ~20% of patients relapse, signifying the urgent need for novel therapeutics for CLL patients especially those with refractory/relapse (ref/rel) disease. Additionally, various tumor microenvironment (TME) stimuli fuel CLL growth and contribute to drug resistance through the activation of numerous signaling pathways (BCR, CD40R, TLR, BAFFR) and consequential sustained NF-κB activation. Currently, there are no FDA approved drugs that effectively target the NF-κB protein family. Herein we introduce 36-286 (N3), a novel spirocyclic dimer which displays NF-κB inhibitory activity and elicits potent anti-leukemic properties. N3 is a dimer of a spirocyclic α-methylene-γ-butyrolactone analog that covalently binds to surface exposed cysteine residues on NF-κB proteins (IKKβ and P65) (Rana S et al, 2016). Our study aims to investigate N3's mode of action (MOA) and to establish its anti-leukemic effects in CLL including drug-resistant disease, thereby introducing a novel therapeutic option for rel/ref disease.Methods: Cell growth via MTS proliferation assay was determined following treatment with N3 (0.125 - 2 μM) in a panel of malignant B cell lines [CLL (HG3, MEC1, OSUCLL), diffuse large B cell lymphoma (Pfeiffer, RC, RIVA), mantle cell lymphoma (Jeko1)], and in patient derived CLL cells stimulated with CpG ODN 2006 (CpG; 3.2 μM). Viability testing of normal B cells isolated from healthy donors was conducted following N3 treatment. Anti-tumor properties of N3 (1 - 2 μM; 4h) in the HG3 and OSUCLL cell lines were further confirmed under conditions mimicking different TME stimuli such as α-IgM (10 μg/mL), CD40L (100 ng/mL), BAFF (50 ng/mL) or CpG (3.2 μM). Protein expression of oncogenic MYC, select NF-κB pathway proteins (IKKα, IKKβ, P65, IκBα, RelB) and the anti-apoptotic protein MCL1 was determined following treatment with N3 (0.25 - 2 μM; 4h) by immunoblot (IB). Next, we induced IBR resistance in HG3 cells by prolonged exposure to increasing IBR concentrations (~10-15 fold its IC 50 in parental cells). Cell proliferation via MTS was determined following treatment with N3 on these resistant cells. To gain insight on the potential MOA of N3 in CLL, we adapted a proteomics-based approach (TMT labeled mass spectrometry) and conducted RNA-seq in OSUCLL cells treated with N3 (1 - 2 μM) for up to 24 h. Subsequent pathway analysis was performed to identify the top factors modulated by N3.Results: N3 showed remarkable efficacy (IC 50 < 0.6 μM) across all the malignant B cell lines evaluated while sparing normal B cells. In CpG stimulated primary CLL, N3 resulted in marked anti-leukemic effects (0.125 μM) comparable to IBR (1 μM). N3 induced cell apoptosis in CLL cell lines in a dose-dependent manner with marked PARP cleavage. Furthermore, our IB analyses of N3 treated CLL cell lines showed reduced levels of NF-κB pathway proteins, MYC and MCL1. Notably, N3 was effective in reducing levels of the above-mentioned proteins in the presence of the various TME stimuli. Strikingly, N3 maintained its cytotoxic effects in ibrutinib resistant HG3 cells. Studies to confirm N3's cytotoxicity in VEN resistant CLL cells are ongoing. Top ten pathways from both proteomics and RNA-seq analyses revealed an upregulation of the unfolded protein response (UPR) and inhibition of cap-dependent protein translation. IB analyses of select factors related to UPR (CHOP, XBP1, PERK, IRE1) and protein translation (eIF2α, 4E-BP1, PDCD4) in N3 treated CLL cells validated our omics' findings. Efforts to identify the proteome wide direct targets of N3 in CLL cells are currently underway.Conclusion: N3 is a novel pre-therapeutic lead that targets multiple survival and proliferation pathways through the inhibition of NF-κB activity and upregulation of UPR. We show that its highly cytotoxic in tumor B cells while sparing normal B cells. Moreover, N3 sustained its anti-tumor properties under different TME stimuli and in IBR resistant cells, indicating the potential use of this compound in rel/ref patients following evaluation in murine CLL models. DisclosuresNo relevant conflicts of interest to declare.

A Modified MTS Proliferation Assay for Suspended Cells to Avoid the Interference by Hydralazine and β-Mercaptoethanol.

The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay is one of the most commonly used tests of cell proliferation. Hydralazine has been reported to interfere with the performance of the MTS assay when used on adherent cells. This study aimed to investigate whether hydralazine interferes with the performance of the MTS assay on suspended cells. THP-1 (a monocytic leukemia cell line) cells were cultured in the presence or absence of hydralazine (0, 10, 50, 100, and 500 μM) for 2 or 24 h. Cell numbers were analyzed using the MTS, trypan blue exclusion, or microscopic assays. A modified version of the standard MTS assay was established by centrifuging the cells and replacing the test medium with fresh culture medium immediately before the addition of the MTS reagent. Culture of THP-1 cells with hydralazine at concentrations of 50, 100, and 500 μM for 2 h increased absorbance (p < 0.001) in the standard MTS assay, whereas both the trypan blue exclusion assay and microscopy suggested no change in cell numbers. Culture of THP-1 cells with 100 and 500 μm hydralazine for 24 h increased absorbance (p < 0.05) in the standard MTS assay; however, trypan blue exclusion and microscopy suggested a decrease in cell numbers. In a cell-free system, hydralazine (100 and 500 μM) increased absorbance in a time- and concentration-dependent manner. The modified MTS assay produced results consistent with trypan blue exclusion and microscopy using THP-1 cells. In addition, the modified MTS assay produced reliable results when K562 and Jurkat cells were incubated with hydralazine or β-mercaptoethanol (βME). In conclusion, a simple modification of the standard MTS assay overcame the interference of hydralazine and βME when assessing suspended cells.

Inhibition of de novo pyrimidine synthesis augments Gemcitabine induced growth inhibition in an immunocompetent model of pancreatic cancer.

Leflunomide (Lef) is an agent used in autoimmune disorders that interferes with DNA synthesis. De Novo pyrimidine synthesis is a mechanism of Gemcitabine (Gem) resistance in pancreatic cancer. This study aims to assess the efficacy and changes in the tumor microenvironment of Lef monotherapy and in combination with Gem, in a syngeneic mouse model of pancreatic cancer.Methods: MTS proliferation assays were conducted to assess growth inhibition by Gem (0-20 nM), Lef (0-40 uM) and Gem+Lef in KPC (KrasLSL.G12D/+;p53R172H/+; PdxCretg/+) cells in vitro. An in vivo heterotopic KPC model was used and cohorts were treated with: PBS (control), Gem (75 mg/kg/q3d), Lef (40 mg/kg/d), or Gem+Lef. At d28 post-treatment, tumor burden, proliferation index (Ki67), and vascularity (CD31) were measured. Changes in the frequency of peripheral and intratumoral immune cell subsets were evaluated via FACS. Liquid chromatography-mass spectrometry was used for metabolomics profiling.Results: Lef inhibits KPC cell growth and synergizes with Gem in vitro (P<0.05; Combination Index 0.44 (<1 indicates synergy). In vivo, Lef alone and in combination with Gem delays KPC tumor progression (P<0.001). CTLA-4+T cells are also significantly decreased in tumors treated with Lef, Gem or in combination (Gem+Lef) compared to controls (P<0.05). Combination therapy also decreased the Ki67 and vascularity (P<0.01). Leflunomide inhibits de novo pyrimidine synthesis both in vitro (p<0.0001) and in vivo (p<0.05).Conclusions: In this study, we demonstrated that Gem+Lef inhibits pancreatic cancer growth, decrease T cell exhaustion, vascularity and as proof of principle inhibits de novo pyrimidine synthesis. Further characterization of changes in adaptive immunity are necessary to characterize the mechanism of tumor growth inhibition and facilitate translation to a clinical trial.

A Novel Therapy-Resistance Transcriptional Signature Based on Single Cell Analysis in Kydar Clinical Trial

Substantial progress in the treatment of Multiple Myeloma (MM) extends survival for many patients (Pts), though most Pts eventually relapse and become therapy refractory. Patients with induction resistant multiple myeloma (IRMM), either primary refractory or early (≤18 months) relapse, have a particularly compromised survival. New treatment strategies and molecular biomarkers for patient stratification and effective clinical care are needed. We previously reported outcomes of KYDAR (NCT04065789) single-arm prospective clinical trial, in which pts primary resistant to a bortezomib-based induction achieved high rates of durable responses when treated with carfilzomib/daratumumab/lenalidomide/dexamethasone (Cohen YC et al. Blood (2019) 134 (Suppl 1): 982). We applied comprehensive single cell RNA-seq analysis of plasma cells (PCs) obtained from longitudinal bone marrow aspirate samples, taken from KYDAR participants (n=34), compared to newly diagnosed MM Pts (n=15) and to healthy controls (n=11). We discovered a novel MM resistance signature differentially expressed between IRMM and newly diagnosed MM groups. This "gene module is enriched for several pathways that were perturbed in the IRMM Pts, including mitochondrial stress genes, the ER and UPR pathway, and the proteasome machinery. Furthermore, differential gene expression analysis between KYDAR responders and non-responders unveil potentially druggable escape mechanisms. These include upregulation of genes associated with immune regulation, proteasome, apoptotic and ER-stress pathways, e.g. Cyclophilin A (PPIA) creating an elaborated signature and potential target list of pathways and escape mechanisms from a highly potent quadruple therapy. This signature includes many novel genes which were not previously described in the context of MM (Fig 1A). Here we report external validation of this novel resistance signature among 908 MM Pts in the MMRF CoMMpass dataset. We found that our genes signature expression follows a normal distribution with no apparent sub-populations in naïve patients, but when examining Pts after multiple relapses, we detected gradient increase in our signature with a clear bi-model distribution (Fig. 1B). The prevalence of high module-1 expression was 5% in newly diagnosed Pts vs 14% in Pts in 3rd or subsequent relapse (p&amp;lt;0.001). Survival analysis on MMRF "module 1 high" (module 1 score &amp;gt; 200) Pts (n = 68) compared with the rest of the population (n = 711) revealed a striking hazard-ratio of 3.9 (2.22 - 6.87) with p-value = 4.57x10-17 (Fig 1C). Module-1 was highly predictive of treatment outcome in KYDAR trials, beyond FISH cytogenetics (Fig 1D). We hypothesized that PPIA may function as a protective resistance gene in MM malignant cells, by accelerating protein folding pathways and reducing stress associated to proteasome inhibitors. In order to test whether PPIA is merely a marker for highly resistant patients or has a causal role in MM resistance to proteasome inhibitors, we used Cyclosporine A (CsA), a known inhibitor of PPIA, in a series of in vitro experiments, to explore it's potential synergy with carfilzomib, a proteasome inhibitor, on RPMI-8226 and U266B MM cell lines, expressing high levels of PPIA. Using MTS proliferation assay, we found that the combined CsA and carfilzomib therapy was significantly more effective than carfilzomib alone. Apoptosis as measured by Propidium Iodide, DAPI and Annexin V FITC staining, was dramatically increased in the combination therapy setting compared to carfilzomib or CsA monotherapy (Fig 1E). In summary, our study defines a roadmap for combining single cell RNA-seq profiling with clinical trials. We reveal and externally-validate a novel transcriptional signature for therapy resistance. We show inhibition of PPIA, a potential target identified, by CsA, overcomes relative resistance of MM cell lines to carfilzomib. We anticipate that such studies will significantly improve the ability to define mechanism of action of treatment, molecularly characterize the Pts that may benefit from the treatment, and reveal potential novel targets. Disclosures Tadmor: AbbVie: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Sanofi: Consultancy, Speakers Bureau; Medison: Consultancy, Speakers Bureau; Neopharm: Consultancy, Speakers Bureau; 6. Novartis Israel Ltd., a company wholly owned by Novartis Pharma AG: Consultancy, Speakers Bureau.

Effects of hyperinsulinemia on acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitor via the PI3K/AKT pathway in non-small cell lung cancer cells in vitro.

Patients with lung cancer harboring activating epidermal growth factor (EGFR) mutations and pre-existing diabetes have been demonstrated to exhibit poor responses to first-line EGFR-tyrosine kinase inhibitor (TKI) therapy. Strategies for the management of acquired resistance to EGFR-TKIs in patients with advanced non-small cell lung cancer (NSCLC) are urgently required. Only a limited number of studies have been published to date on the effects of insulin on EGFR-TKI resistance in NSCLC. Hence, the aim of the present study was to investigate the roles of hyperinsulinemia and hyperglycemia in mediating gefitinib resistance in NSCLC cells with activating EGFR mutations. In the present study, the HCC4006 cell line, which harbors EGFR mutations, was co-treated with gefitinib and long-acting insulin glargine. Whether hyperinsulinemia is able to mediate EGFR-TKI resistance in the NSCLC cell line harboring activating EGFR mutations was also investigated, and the possible underlying mechanisms responsible for these actions were explored. The inhibition of cell proliferation, and the potential mechanism of gefitinib resistance, were examined using an MTS proliferation assay and western blot analysis, and through the transfection of siRNAs. Whether the inhibition of AKT is able to overcome EGFR-TKI resistance induced by long-acting insulin was also investigated. The results obtained suggested that hyperinsulinemia induced by glargine upregulated NSCLC cell proliferation and survival, and induced gefitinib resistance. By contrast, the morphology and proliferation of the cells in a medium containing a 2-fold concentration of glucose were not significantly affected. Gefitinib resistance induced by hyperinsulinemia may have been mediated via the phosphoinositide 3-kinase (PI3K)/AKT pathway rather than the mitogen-activated protein kinase extracellular signal regulated kinase (MAPK/ERK) pathway. AKT serine/threonine kinase 1 knockdown by siRNA rescued the gefitinib resistance that was induced by hyperinsulinemia. In conclusion, hyperinsulinemia, but not hyperglycemia, was identified to cause the development of gefitinib resistance in NSCLC cells with activating EGFR mutations. However, additional studies are required to investigate strategies, such as co targeting hyperinsulinemia and the PI3K/AKT pathway, for overcoming EGFR-TKI resistance in patients with NSCLC.

Abstract 1755: Prodigiosin inhibits the proliferation and migration of mcf-7 breast cancer cells through the demethylation of mir-200c gene

Abstract Background: DNA methylation in microRNA (miRNA) host genes is associated with the down-regulation of gene expression in tumorigenesis and progression. Accumulating evidence shows that low levels of miR-200c were correlated with a worse prognosis in breast cancer. MiRNA promoter methylation has been reported as a major cause of miR-200c downregulation. Prodigiosin (PG), red bacterial pigment with a pyrrolylpyrromethene skeleton, has significant antibacterial, antifungal, antimalarial and antitumor activity via the modulation of multiple cell signaling pathways against a variety of human cancer cells. However, there is little information regarding the epigenetic-based effects of Prodigiosin in breast cancer. In this study, we hypothesize that Prodigiosin has anti-proliferative and anti-migration effects on breast cancer cells through the demethylation of miR-200c. Material and Methods: MCF-10A breast epithelial cells and MCF-7 breast cancer cells were used to investigate the effects of Prodigiosin on the expression and methylation of miR-200c using real time-PCR (RT-qPCR) and methylation-specific PCR (qMSP), respectively. MTS proliferation assay, cell scratch assay and three-dimensional (3D) formation assay were performed to assess the effect of Prodigiosin on the proliferation and migration of MCF-7 breast cancer cells. Result: MCF-7 breast cancer cells showed significant hypermethylation of miR-200c, and significantly down-regulated miR-200c expression compared to MCF-10A breast epithelial cells. Prodigiosin treatment led to significant inhibition of proliferation and migration, and significantly up-regulated miR-200c expression, whereas the methylation level of miR-200c significantly decreased in MCF-7 breast cancer cells. Conclusion: Prodigiosin, a secondary metabolite of bacteria, inhibits the proliferation and migration of breast cancer cells, and restores the demethylation status and expression of miR-200c. These findings elucidate that the demethylation of miR-200c may be a molecular mechanism underlying the anti-tumor of Prodigiosin in breast cancer. Citation Format: Fengqin Shi, Lingeng Lu, Peng LV, Ya Li, Hou Li, Xinyi Chen, Yong Zhu. Prodigiosin inhibits the proliferation and migration of mcf-7 breast cancer cells through the demethylation of mir-200c gene [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1755.

Abstract 566: Therapeutic targeting of the polyamine pathway and EIF5A1 hypusination in endometrial cancer with DFMO and GC7

Abstract The polyamines putrescine, spermidine, and spermine are well-characterized oncometabolites upregulated in cancers and drive their proliferation and spread. Endometrial cancers (ECs) express high levels of ornithine decarboxylase (ODC), a rate-limiting enzyme of polyamine biosynthesis and decreased levels of spermidine/spermine N1-acetyltransferase (SAT1), a key negative regulator of polyamines. In addition, the deoxyhypusine synthase (DHPS) enzyme necessary for spermidine-dependent hypusination of eIF5A1 is highly expressed in ECs. Hypusinated EIF5A1 is needed by cancer cells to support their increased protein translation needs. Collectively, these findings suggest that the polyamine pathway is particularly active and necessary in EC. Here we evaluated the effect of ODC inhibitor difluoromethylornithine (DFMO) and DHPS inhibitor N1-Guanyl-1,7-Diaminoheptane (GC7) alone or in combination on the growth of ECs. GC7 and DFMO were effective in suppressing growth in EC cell lines in vitro as measured by MTS viability and proliferation assays. These effects were accompanied by decreased hypusinated EIF5A1 in treated cells. However, neither compound induced apoptotic cell death when applied singly. We did note that when non-apoptotic inducing doses of DFMO and GC7 were combined, EC cells showed a marked combinatorial decrease in viability, proliferation, and hypusinated EIF5A1 levels. Importantly we found that combined DFMO/GC7 treatment caused apoptotic cell death of EC cells as measured by cleaved PARP. Furthermore, levels of cleaved caspases 3 and 7 were increased in these cells while caspases 5 or 9 were not cleaved. In summary we found for the first time that pharmacologically increased depression of the polyamine pathway as measured by decreased hypusinated EIFA1 can lead to apoptotic cell death in ECs. These data suggest that targeting the polyamine pathway and particularly its role in protein translation through EIF5A1 hypusination may be an effective treatment strategy. Citation Format: HongIm Kim, Chad Schultz, Andre Bachmann, John I. Risinger. Therapeutic targeting of the polyamine pathway and EIF5A1 hypusination in endometrial cancer with DFMO and GC7 [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 566.

Upregulation of long non-coding RNA FOXD2-AS1 promotes progression and predicts poor prognosis in tongue squamous cell carcinoma.

Accumulating evidences suggest that lncRNA FOXD2-AS1 plays an important role in tumor progression, however, its function in tongue squamous cell carcinoma (TSCC) remains unknown. This research aims to investigate the function and mechanism of FOXD2-AS1 in the modulation of tongue squamous cell carcinoma progression. Expression of FOXD2-AS1 was detected in TSCC tissues and TCGA data. Receiver operating characteristic curves (ROCs) analysis and bioinformatic analysis of TCGA data were performed to investigate the role of FOXD2-AS1 in TSCC prognosis. After siRNA-mediated downregulation of FOXD2-AS1, wound healing assay, Transwell migration and invasion assays, and MTS proliferation assay were conducted to explore the effects that FOXD2-AS1 exerted on SCC-9 and CAL-27 cell lines. Western blotting was performed to detect the downstream protein changes. Compared to the normal tissues and samples, FOXD2-AS1 significantly highly expressed in TSCC tissues and in TSCC samples of TCGA data, and high expression of FOXD2-AS1 was associated with lymphatic metastasis and poor TNM stages. ROC analysis and bioinformatic analysis of TCGA data further suggested that high expression of FOXD2-AS1 was associated with TSCC poor prognosis. Downregulation of FOXD2-AS1 inhibited the migration and invasion of SCC-9 and CAL-27 cell lines. Western blotting showed that the expression of p-p44 and p-p65 downregulated after FOXD2-AS1 knockdown. High expression of FOXD2-AS1 promotes TSCC progression through modulating NF-kB and ERK MAPK signaling pathways and is associated with TSCC poor prognosis, it could be a novel therapeutic target and prognostic biomarker for TSCC.

Kinesin KIF18A is a novel PUM-regulated target promoting mitotic progression and survival of a human male germ cell line.

Regulation of proliferation, apoptosis and cell cycle is crucial for the physiology of germ cells. Their malfunction contributes to infertility and germ cell tumours. The kinesin KIF18A is an important regulator of those processes in animal germ cells. Post-transcriptional regulation of KIF18A has not been extensively explored. Owing to the presence of PUM-binding elements (PBEs), KIF18A mRNA is a potential target of PUM proteins, where PUM refers to Pumilio proteins, RNA-binding proteins that act in post-transcriptional gene regulation. We conducted RNA co-immunoprecipitation combined with RT-qPCR, as well as luciferase reporter assays, by applying an appropriate luciferase construct encoding wild-type KIF18A 3'-UTR, upon PUM overexpression or knockdown in TCam-2 cells, representing human male germ cells. We found that KIF18A is repressed by PUM1 and PUM2. To study how this regulation influences KIF18A function, an MTS proliferation assay, and apoptosis and cell cycle analysis using flow cytometry, was performed upon KIF18A mRNA siRNA knockdown. KIF18A significantly influences proliferation, apoptosis and the cell cycle, with its effects being opposite to PUM effects. Repression by PUM proteins might represent one of mechanisms influencing KIF18A level in controlling proliferation, cell cycle and apoptosis in TCam-2 cells.

Stromal vascular fraction promotes migration of fibroblasts and angiogenesis through regulation of extracellular matrix in the skin wound healing process

BackgroundA refractory wound is a typical complication of diabetes and is a common outcome after surgery. Current approaches have difficulty in improving wound healing. Recently, non-expanded stromal vascular fraction (SVF), which is derived from mature fat, has opened up new directions for the treatment of refractory wound healing. The aim of the current study is to systematically investigate the impact of SVF on wound healing, including the rate and characteristics of wound healing, ability of fibroblasts to migrate, and blood transport reconstruction, with a special emphasis on their precise molecular mechanisms.MethodsSVF was isolated by digestion, followed by filtration and centrifugation, and then validated by immunocytochemistry, a MTS proliferation assay and multilineage potential analysis. A wound model was generated by creating 6-mm-diameter wounds, which include a full skin defect, on the backs of streptozocin-induced hyperglycemic mice. SVF or human adipose-derived stem cell (hADSC) suspensions were subcutaneously injected, and the wounds were characterized over a 9-day period by photography and measurements. A scratch test was used to determine whether changes in the migratory ability of fibroblasts occurred after co-culture with hADSCs. Angiogenesis was observed with human umbilical vein endothelial cells. mRNA from fibroblasts, endotheliocyte, and skin tissue were sequenced by high-throughput RNAseq, and differentially expressed genes, and pathways, potentially regulated by SVF or hADSCs were bioinformatically analyzed.ResultsOur data show that hADSCs have multiple characteristics of MSC. SVF and hADSCs significantly improved wound healing in hyperglycemic mice. hADSCs improve the migratory ability of fibroblasts and capillary structure formation in HUVECs. SVF promotes wound healing by focusing on angiogenesis and matrix remodeling.ConclusionsBoth SVF and hADSCs improve the function of fibroblast and endothelial cells, regulate gene expression, and promote skin healing. Various mechanisms likely are involved, including migration of fibroblasts, tubulogenesis of endothelial cells through regulation of cell adhesion, and cytokine pathways.

Abstract 27: Identification and characterization of a novel dual FLT3/microtubule polymerization inhibitor through cell-based screening

Abstract Activating mutations in FLT3 receptor tyrosine kinase are found in one-third of acute myeloid leukemia (AML) patients and are associated with disease relapse and bad prognosis. Majority of these mutations are Internal tandem duplications (ITD) in the juxtamembrane domain of FLT3 and have been validated as a therapeutic target. Clinical success of selective inhibitors targeting oncogenic FLT3, however, has been limited due to the acquisition of drug resistance. Here we report the identification of a dual FLT3/microtubule polymerization inhibitor, HH-IA-208, through cell-based screenings for the differential killing of leukemia cell lines expressing FLT3-ITD (MV411) or BCR-ABL (K562) using an MTS proliferation assay and for mitotic inducers using a dot-blot assay for histone H3 phosphorylation in HCT116 cell line. HH-IA-208, a chalcone derivative, inhibits FLT3 in vitro and treatment of FLT3-ITD+ cell lines with HH-IA-208 results in reduced FLT3 signaling. Similarly, HH-IA-208 inhibits tubulin polymerization in a biochemical assay and in cells that results in a mitotic arrest. HH-IA-208 is selectively more potent in leukemia cell lines expressing FLT3-ITD and treatment for 24 and 48 hours with the inhibitor results in apoptotic cell death. Furthermore, HH-IA-208 is able to overcome TKD mutation-mediated acquired resistance to FLT3 inhibitors in a MOLM13 cell line expressing FLT3-ITD with the D835Y mutation. HH-IA-208, therefore, is a promising lead for the discovery of dual target FLT3 inhibitors that can overcome resistance to selective FLT3 inhibitors. Citation Format: Haleema Sadia Malik, Aishah Bilal, Rahim Ullah, Maheen Iqbal, Rahman Shah Saleem, Hidayat Hussain, Amir Faisal. Identification and characterization of a novel dual FLT3/microtubule polymerization inhibitor through cell-based screening [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 27.

Human Novel MicroRNA Seq-915_x4024 in Keratinocytes Contributes to Skin Regeneration by Suppressing Scar Formation

Early in gestation, wounds in fetal skin heal by regeneration, in which microRNAs play key roles. Seq-915_x4024 is a novel microRNA candidate confirmed by deep sequencing and mirTools 2.0. It is highly expressed in fetal keratinocytes during early gestation. Using an in vitro wound-healing assay, Transwell cell migration assay, and MTS proliferation assay, we demonstrated that keratinocytes overexpressing seq-915_x4024 exhibited higher proliferative activity and the ability to promote fibroblast migration and fibroblast proliferation. These characteristics of keratinocytes are the same biological behaviors as those of fetal keratinocytes, which contribute to skin regeneration. In addition, seq-915_x4024 suppressed the expression of the pro-inflammatory markers TNF-α, IL-6, and IL-8 and the pro-inflammatory chemokines CXCL1 and CXCL5. We also demonstrated that seq-915_x4024 regulates TGF-β isoforms and the extracellular matrix. Moreover, using an in vivo wound-healing model, we demonstrated that overexpression of seq-915_x4024 in keratinocytes suppresses inflammatory cell infiltration and scar formation. Using bioinformatics analyses, luciferase reporter assays, and western blotting, we further demonstrated that Sar1A, Smad2, TNF-α, and IL-8 are direct targets of seq-915_x4024. Furthermore, the expression of phosphorylated Smad2 and Smad3 was reduced by seq-915_x4024. Seq-915_x4024 could be used as an anti-fibrotic factor for the treatment of wound healing.

Cytotoxic effects of S-(+)-Carvone on selected human cancer cell lines

S-(+)-Carvone (S-CVN), the main constituent of Caraway seed (Carum carvi L.Umbelliferae), has been reported to show significant anticancer and chemopreventive effects against several cancer types. The current study aimed to evaluate the cytotoxic effects of S-CVN on four different human cancer cell lines: ovarian cancer (SW-626), triple negative breast cancer (BT-20), prostate cancer (PC-3) and lymphoma (RAJI). Using MTS proliferation assay, S-CVN showed significant concentration-dependent anti-proliferative effects against the chosen cancer cell lines, with IC50 values of 147,117,199 and 228?M in SW-626, PC-3, BT-20 and RAJI, respectively. Mechanistically, S-CVN with its ?,?-unsaturated carbonyl functionality has the potential to interact with cellular nucleophilic functional groups through Michael’s addition type of reaction. The covalent interaction may explain the observed anti-proliferative activity. To further understand the mechanism of S-CVN cytotoxicity, glutathione (GSH and GSSG) were added to SW-626 cell line as pre- and co-treatments with S-CVN. According to results, the cell viability was enhanced and the cytotoxic effect of S-CVN was extremely decreased using a range of GSH/GSSG concentrations (50 -1000?M). Moreover, the interaction between GSH and S-CVN was further confirmed by using thin layer chromatography (TLC). This is presumably attributed to the fact that the nucleophilic thiol function in GSH interacts with S-CVN ?,?-unsaturated ketone moiety at ?-C. The obtained data suggests that the reactivity of the electrophilic functionality of S-CVN plays a crucial role in its cytotoxicity.