Cell Growth Medium Research Articles

Electrochemical Potential Gradient As a Quantitative Test Platform for Cellular Oxidative Stress

Oxidative stress (OS), involved in many biological phenomena, such as aging, carcinogenesis and inflammation, is defined as an imbalance between reactive oxygen species (ROS) and organism’s antioxidant defenses. The consequences of this imbalance lead to the disruption of cellular redox homeostasis and oxidative damage to DNA, proteins and lipids.(1) One metric of the relative strengths of oxidizers implicated in causing pathogenic oxidative damage via ROS production is the effective redox potential experienced by the cells. Therefore, establishing the relationship between the strength of the oxidative action, characterized by redox potential, and the biomolecular consequences is critical to elucidating the thermodynamic framework of oxidative damage. Experiments with OS in the lab environment require subjecting the study object to a given level of oxidative bias relative to biosystem’s natural equilibrium, preferably in a well-defined, reproducible and quantitative fashion. Popular in vitro OS inducers include exogenous chemical agents, ionizing radiation or heat shock. In addition to disrupting redox homeostasis, each of these agents will also have a specific chemical interaction with cell components, which have to be accounted for during interpretation.(2) Here, we describe a novel way to create an OS environment for surface attached Chinese Hamster Ovary (CHO) cells by exposing them to an electrochemical potential gradient. With this technique we can apply a stable linear potential profile over a cell monolayer, thus providing an efficient method to screen live cell response to an exogenous redox background. It is based on a bipolar electrode configuration (3), adapted for a rectangular cell growth flask. A constant current is produced in cell media, thus generating an electric field and potential drop over the mammalian cell monolayer. Surface attached cells experience varying electrochemical potential, depending on their location along the current axis. Subsequently, cell viability gradients were produced within a range of treatment levels. The live-dead assay fluorescence image of the flask bottom slide shows the CHO cell condition following incubation under the redox potential gradient for a fixed time interval (see Figure). Images contain a rather uniform live, dead and a narrow changeover region ( magnified view in the lower panel of Figure ), consistent with a commencement of cell death at increasingly positive solution redox potential. The cell viability ratio was calculated from integrated pixel density. Therefore, the sigmoidal cell viability curve shape, produced when cells are exposed to the electrochemical potential gradient , is consistent with a two state conversion model and could be numerically characterized by a half maximum effective potential. This concept is widely used to describe dose-response curves in toxicology. Such numerical values would be useful to compare cell viability when subjected to oxidative stress in diverse experimental circumstances. That way, the higher effective potential value would indicate the increase in cell viability or the efficacy of the antioxidant. We have compared CHO cell response when exposed to three hydrogen peroxide concentrations (20 mM, 50 mM, and 100 mM) with the exposure to electrochemically induced potential gradient. Redox potential values of these H2O2 preparations were measured in separate experiments 1h after hydrogen peroxide was diluted into the cell growth media. Remarkably, cell viability vs solution redox potential dependencies are very close suggesting that exogenous hydrogen peroxide causes CHO cell OS largely by a positive shift in the solution redox potential, at least in this concentration range. Our test platform allows for direct imaging and analysis of cell viability, exposed to a range of electrochemical potentials. The slide vessel system can readily be adapted for other cellular assays such as ROS detection, apoptosis, etc. The system is particularly useful for providing a linear range of oxidative and reductive potentials in a single experiment. By replacing the vessel contents before during and after treatment a wide range of solution conditions can be tested and cell images can be acquired during oxidative treatment. This is particularly useful for in vitro testing of the effectiveness of additives such as anti-oxidants as it enables monitoring a real time cellular response. In addition, various cell types including cancer cell lines can be compared in their resistance to oxidative potentials and effectiveness of various drugs. Figure 1. Overlay of the fluorescence images of the cell growth flask bottom following the application of the electrochemical potential gradient and live-dead staining (left-live, right-dead). References (1) Halliwell, B. Trends Pharmacol Sci 2013, 34, 301. (2) Buettner, G. R.; Wagner, B. A.; Rodgers, V. G. J. Cell Biochem Biophys 2013, 67, 477. (3) Fleischmann, M.; Ghoroghchian, J.; Rolison, D.; Pons, S. J Phys Chem-Us 1986, 90, 6392. Figure 1

Cytotoxic activity of selenosulfate versus selenite in tumor cells depends on cell line and presence of amino acids.

Based on acute cytotoxicity studies, selenosulfate (SeSO3 (-)) has been suggested to possess a generally higher toxic activity in tumor cells than selenite. The reason for this difference in cytotoxic activity remained unclear. In the present study, cytotoxicity tests with human hepatoma (HepG2), malignant melanoma (A375), and urinary bladder carcinoma cells (T24) showed that the selenosulfate toxicity was very similar between all three tested cell lines (IC50 6.6-7.1μM after 24h). It was largely independent of exposure time and presence or absence of amino acids. What changed, however, was the toxicity of selenite, which was lower than that of selenosulfate only for HepG2 cells (IC50 > 15μM), but similar to and higher than that of selenosulfate for A375 (IC50 4.7μM) and T24 cells (IC50 3.5μM), respectively. Addition of amino acids to T24 cell growth medium downregulated short-term selenite uptake (1.5 versus 12.9ngSe/10(6) cells) and decreased its cytotoxicity (IC50 8.4μM), rendering it less toxic than selenosulfate. The suggested mechanism is a stronger expression of the xc (-) transport system in the more sensitive T24 compared to HepG2 cells which creates a reductive extracellular microenvironment and facilitates selenite uptake by reduction. Selenosulfate is already reduced and so less affected. The cytotoxic activity of selenosulfate and selenite to tumor cells therefore depends on the sensitivity of each cell line, supplements like amino acids as well as the reductive state of the extracellular environment.

English

The steroid metabolites 9-hydroxy-androstenedione (9-OH-AD), androstadienedione (ADD) and androstenedione (AD) are important steroidal pharmaceuticals. In order to raise the production of steroid metabolites, an efficient resting cell phytosterol bioconversion process was developed to produce 9-OH-AD in the presence of hydroxypropyl-b-cyclodextrin (HP-b-CD). Cell growth medium containing phytosterol as an inducer positively improved cell activity. Under aerobic conditions, bioconversion proceeded at 70 g L –1 phytosterol in the presence of HP-b-CD (the optimized molar ratio of HP-b-CD/phytosterol was 1:1) with 30 g L –1 resting Mycobacterium neoaurum NwIB-yV cells (cell dry mass) in a 5-L bioreactor, where 9-OH-AD production and space-time yield reached 36.4 g L –1 and 9.1 g L –1 d –1 , respectively. The recycling of cells and HP-b-CD enables cost-saving and industrial applications. This bioprocess was also applied for the production of ADD and AD. The production of these steroid metabolites was much higher than that reported in previous studies.

Synthesis, characterization and in vitro biocompatibility assessment of a novel tripeptide hydrogelator, as a promising scaffold for tissue engineering applications.

We have synthesized and characterized a self-assembling tripeptide hydrogelator Ac-l-Phe-l-Phe-l-Ala-NH2. A series of experiments showed that the hydrogel material could serve as a stabile and biocompatible physical support as it improves the survival of HEK293T cells in vitro, thus being a promising biomaterial for use in tissue engineering applications.

Molecular features of doxorubicin-resistance development in colorectal cancer CX-1 cell line

Background and aimResistance to chemotherapy is the key obstacle to the effective treatment of various cancers. Accumulating evidence suggests significant involvement of the epithelial-to-mesenchymal transition (EMT) in the chemoresistance of most cancer types. This study aimed at analyzing the gene expression profile of doxorubicin (DOX)-resistant colorectal cancer cells CX-1. Materials and methodsDOX-resistant CX-1 cell sublines were acquired by stepwise increment of DOX concentrations in cell growth media. Global gene expression profiling was performed using human gene expression microarrays. The expression levels of individual genes were assessed by means of quantitative PCR (qPCR), while the DNA methylation pattern of several selected genes was determined by methylation-specific PCR. ResultsFour DOX-resistant CX-1 sublines were established as a valuable tool for cell chemoresistance studies. Altered expression of the EMT, cell adhesion and motility, and chemoresistance-related genes was observed in DOX-resistant cells by genome-wide gene expression analysis. Besides, early and significant upregulation of the key EMT genes ZEB1 (5.8×; P<0.001) and CDH2 (6.2×; P=0.044) was identified by qPCR, with subsequent activation of drug transporter gene ABCC1 (3.3×; P=0.007) and cell stemness gene NANOG (2.4×; P=0.008). Downregulation of TET1 (2.1×; P=0.041) and changes in the methylation status of the p16 gene were also involved in the acquisition of cell resistance to DOX. ConclusionThe results of our study suggest possible involvement of the key EMT and drug transporter genes in the early phase of cancer cell chemoresistance development.

Tripeptide consisting of benzyl protected di-cysteine and phenylalanine forms spherical assembly and induces cytotoxicity in cancer cells via apoptosis

Tripeptide self assemblies in cell growth medium induce apoptosis and promoting cancer cell death at submicromolar concentration.

Selective Release of Aromatic Heterocycles from Ruthenium Tris(2-pyridylmethyl)amine with Visible Light.

Three complexes of the general formula [Ru(TPA)L2](PF6)2 [TPA = tris(2-pyridylmethyl)amine], where L = pyridine (1), nicotinamide (2), and imidazole (3), were prepared and characterized spectroscopically. X-ray crystallographic data were obtained for 1 and 3. Complexes 1-3 show strong absorption in the visible region and selective release of heterocycles upon irradiation with visible light. Time-dependent density functional theory calculations are consistent with the presence of singlet metal-to-ligand charge-transfer bands in the visible region in 1-3. Caged heterocycles 1-3 are highly stable in solution in the dark, including in cell growth media. Cell viability data show no signs of toxicity of 1-3 against PC-3 cells at concentrations up to 100 μM under light and dark conditions, consistent with Ru(TPA) acting as a nontoxic and effective photocaging group for aromatic heterocycles.

Concomitantly Targeting BCL-2 with Venetoclax (ABT-199/GDC-0199) and MAPK Signaling with Cobimetinib (GDC-0973) in Acute Myeloid Leukemia Models

Pro-survival molecules including BCL-2 play critical roles in leukemia transformation and chemoresistance. ABT-199/GDC-0199 (venetoclax) is an orally available BH3-mimetic that binds with high affinity to BCL-2, but lacks affinity for BCL-XL and MCL-1. We have recently demonstrated anti-leukemia potency of venetoclax in acute myeloid leukemia (AML) models (Pan et al. Cancer Discovery 2014). However, venetoclax poorly inhibits MCL-1, causing resistance in leukemia cells that rely on MCL-1 for survival. The RAF/MEK/ERK (MAPK) cascade is a major effector pathway in AML that is activated by upstream mutant proteins such as FLT3, KIT and RAS. Additionally, the MAPK pathway regulates BCL-2 family proteins by stabilizing anti-apoptotic MCL-1 and inactivating pro-apoptotic BIM. In this study, we evaluated the anti-tumor effects of concomitant BCL-2 and MAPK blockade by venetoclax in combination with MEK1/2 inhibitor GDC-0973 (cobimetinib)..We initially examined activity of these agents in a panel of myeloid leukemia cell lines with diverse genetic alterations (Fig. 1A). The IC50 values of cobimetinib ranged from < 0.01 µM to > 1 µM after 72 hours of drug treatment but did not correlate with the basal level of p-ERK1/2. In 7 out of 11 cell lines, combination of the agents elicited synergistic growth inhibition. Notably synergism of venetoclax with cobimetinib was observed in venetoclax-resistant cell lines (MOLM14, OCI-AML3, NB4 and THP1). Ongoing analysis of pharmacodynamic markers include transcriptome assessment by RNA sequencing, functional proteomics by reverse phase protein array (RPPA) and quantification of BCL-2:BIM and MCL-1:BIM complexes using the electrochemiluminescent ELISA assay (Meso Scale Discovery, MSD-ELISA). The preliminary MSD data revealed that BCL-2:BIM complex was disrupted in most cell lines and accumulated following cobimetinib treatment, which may be due to the disruption of MCL-1:BIM complex by inhibition of MEK (Fig. 1B).In a long-term culture of primary AML blasts in serum-free stem cell growth medium supplemented with cytokines and StemRegenin 1 (SR1) to main the immature state of leukemia cells, the combination of venetoclax and cobimetinib induced distinct apoptotic cell death, with AML #1 sensitive to venetoclax but resistant to cobimetinib. Alternatively, AML #2 and #3 samples were resistant to venetoclax but sensitive to cobimetinib and the combination of both drugs (Fig. 1C). We next investigated signaling patterns and BCL-2 family protein expression in AML stem/progenitor cells using a 34-antibody panel and time-of-flight mass cytometry (CyTOF). In AML#1, BCL-2 was expressed in leukemia blasts, with enrichment in a progenitor AML population phenotypically defined as CD45dim CD34+ CD38+ CD123+ CD33+ (Fig. 1D). The high expression level of BCL-2 and low expression of MCL-1 and BCL-XL may account for sensitivity to venetoclax in AML#1. Both basal and G-CSF- or SCF-stimulated p-ERK was efficiently down-regulated by cobimetinib; however, G-CSF-evoked p-STAT3/5 and SCF-induced p-AKT were only slightly reduced (Fig. 1E). Notably we observed increased phosphorylation of STAT5 pathway upon treatment with cobimetinib, suggesting that active MAPK signals inhibit phosphorylation of the JAK-STAT pathway, as previously reported (Krasilnikov et al. Oncogene, 2003 and Lee at al. Cancer Cell, 2014).To test the efficacy of both compounds in vivo, we injected NSG mice with genetically engineered OCI-AML3/Luc/GFP cells. Bioluminescent imaging (BLI) demonstrated significantly reduced leukemia burden in treated groups compared to controls, more prominently in the cobimetinib single agent and venetoclax plus cobimetinib co-treated mice (Fig. 1F). The efficacy study is ongoing and median survival for cobimetinib and venetoclax co-treated mice has yet to be determined (Fig. 1G).In summary, our data demonstrates that combinatorial blockade of MAPK and BCL-2 pathways is synergistic in the majority of AML cell lines tested and can overcome intrinsic resistance to venetoclax. Ongoing studies will evaluate efficacy of this combination therapy in primary human AML xenografts and elucidate mechanisms of synergy. [Display omitted] DisclosuresLeverson:AbbVie: Employment, Equity Ownership. Dail:Genentech: Employment, Equity Ownership. Phillips:AbbVie: Employment, Other: Shareholder, Patents & Royalties. Chen:Abbvie: Employment, Equity Ownership. Jin:Abbvie: Employment, Equity Ownership. Jabbour:Pfizer: Consultancy, Research Funding. Sampath:Genentech: Employment, Equity Ownership. Konopleva:Novartis: Research Funding; AbbVie: Research Funding; Stemline: Research Funding; Calithera: Research Funding; Threshold: Research Funding.

Abstract B18: Targeting histone deacetylase 6 (HDAC6) depresses proliferation and induces caspase-associated cell death in glioblastoma multiforme (GBM) cells and GBM stem cell-like spheroids

Abstract Glioblastoma multiforme (GBM) comprises the most common and very aggressive form of primary brain tumor with a dismal prognosis and very poor response to the current therapies. HDAC inhibitors (HDACi) are capable of inducing growth arrest and apoptosis in various tumor cell types. HDAC6 is a unique enzyme having two deacetylase domains, and a ubiquitin-binding domain. HDAC6 interacts with a number of proteins in the cytoplasm and is involved in tumorigenesis, cell motility, and metastasis. Significantly, it has been shown that HDAC6 knockout mice are viable. Therefore, in this study, we evaluated HDAC6 as a relevant target for GBM treatment by using a potent HDAC6 inhibitor, CAY 10603. Our data showed that CAY 10603 targets the established GBM cell line U86MG, M-HBT161 early primary cultures, and CD133- and SOX2-positive stem cell-like spheroids. CAY 10603 at 1-5 μM triggered significant inhibition of cell survival and induced apoptotic cell death in GBM cells and GBM spheroids. CAY 10603 reduced cell survival in these cells by 50% (IC50) at 1-3 μM treatment for 48 h. Similarly, CAY 10603 induced significant dose-dependent inhibition of spheroid survival in U87MG and M-HBT161 when the spheroids were grown in a defined GBM stem cell (GSC) growth medium on ultra-low attachment plates for four days. Interestingly, when grown in the same medium but on plates which promote attachment, the spheroids were 3-4 fold more sensitive to CAY 10603, indicating that growth conditions affect the sensitivity of GBM stem cell-like spheroids. Moreover, CAY 10603 triggered cell death in U87MG and M-HBT161 cells as well as CD133/SOX2-expressing spheroids was associated with activation of caspases-3, -6 and -9. Overall, our results show that CAY 10603 robustly inhibits the growth of GBM cells, and is effective in eliminating spheroids that contain GBM cancer stem cells which play a major role in drug resistance and disease recurrence. These results suggest that use of CAY 10603 alone or in combination with other agents may potentially improve the survival of brain tumor patients. Citation Format: Mohammad Reza Saadatzadeh, Khadijeh Bijangi Vishehsaraei, Haiyan Wang, Aaron Cohen-Gadol, Karen E. Pollok, Ahmad R. Safa. Targeting histone deacetylase 6 (HDAC6) depresses proliferation and induces caspase-associated cell death in glioblastoma multiforme (GBM) cells and GBM stem cell-like spheroids. [abstract]. In: Proceedings of the AACR Special Conference: Advances in Brain Cancer Research; May 27-30, 2015; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2015;75(23 Suppl):Abstract nr B18.

A Multifunctional Polymer Combining the Imidazole and Zwitterion Motifs as a Biocompatible Compact Coating for Quantum Dots

We introduce a set of multicoordinating imidazole- and zwitterion-based ligands suited for surface functionalization of quantum dots (QDs). The polymeric ligands are built using a one-step nucleophilic addition reaction between poly(isobutylene-alt-maleic anhydride) and distinct amine-containing functionalities. This has allowed us to introduce several imidazole anchoring groups along the polymer chain for tight coordination to the QD surface and a controllable number of zwitterion moieties for water solubilization. It has also permitted the introduction of reactive and biomolecular groups for further conjugation and targeting. The QDs capped with these new ligands exhibit excellent long-term colloidal stability over a broad range of pH, toward excess electrolyte, in cell-growth media, and in the presence of natural reducing agents such as glutathione. These QDs are also resistant to the oxidizing agent H2O2. More importantly, by the use of zwitterion moieties as the hydrophilic block, this polymer design provides QDs with a thin coating and compact overall dimensions. These QDs are easily self-assembled with full size proteins expressed with a polyhistidine tag via metal-histidine coordination. Additionally, the incorporation of amine groups allows covalent coupling of the QDs to the neurotransmitter dopamine. This yields redox-active QD platforms that can be used to track pH changes and detect Fe ions and cysteine through charge-transfer interactions. Finally, we found that QDs cap-exchanged with folic acid-functionalized ligands could effectively target cancer cells, where folate-receptor-mediated endocytosis of QDs into living cells was time- and concentration-dependent.

Effect of osteogenic differentiation medium on proliferation and differentiation of human mesenchymal stem cells in three-dimensional culture with radial flow bioreactor.

Human mesenchymal stem cells (hMSCs) are multipotent cells, and have been expanded and differentiated into several kinds of mesodermal tissue in vitro. In order to promote bone repair, enhancement of the proliferation and differentiation of hMSCs into osteoblasts in vitro is recommended prior to therapeutic delivery. However, for clinical applications, it is still unclear which method is more advanced for tissue engineering: to transplant undifferentiated cells or partially differentiated stem cells. Therefore, the present study aimed to investigate how osteogenic differentiation medium (ODM) affects hMSCs cultured in a 3D scaffold using a radial-flow bioreactor (RFB) besides cell growth medium (GM). To produce precultured sheets, the hMSCs were first seeded onto type 1 collagen sheets and incubated for 12 h, after which they were placed in the RFB for scaffold fabrication. The culture medium was circulated at 3 mL/min and the cells dynamically cultured for 1 week at 37 °C. Static cultivation in a culture dish was also carried out. Cell proliferations were evaluated by histological analysis and DNA-based cell count. Alkaline phosphatase (ALP) activity, immunocytochemical analysis with BMP-2, and osteopontin on the hMSCs in the collagen scaffold were performed. After 14 days of ODM culture, a significant increase in cell number and a higher density of cell distribution in the scaffold were observed after both static and dynamic cultivation compared to GM culture. A significant increase in ALP activity after 14 days of ODM was recognized in dynamic cultivation compared with that of static cultivation. Cells that BMP-2 expressed were frequently observed after 14 days in dynamic culture compared with other conditions, and the expression of osteopontin was confirmed in dynamic cultivation after both 7 days and 14 days. The results of this study revealed that both the proliferation and bone differentiation of hMSCs in 3D culture by RFB were accelerated by culture in osteogenic differentiation medium, suggesting an advantageous future clinical applications for RFB cell culture and cell transplantation for tissue engineering.

Gamma radiation effects on hydrogen-terminated nanocrystalline diamond bio-transistors

Diamond is considered as a promising tissue equivalent material in radiation therapies as well as for bio-electronic sensors due to its unique set of properties. These features are combined in this work where effects of gamma irradiation (60Co, up to 300Gy) on function and stability of microscopic (60×20μm2) hydrogen-terminated diamond (H-diamond) solution-gated field effect transistors (SG-FETs) are studied. The H-diamond SG-FETs were prepared using 300nm thin diamond films deposited on glass from methane and hydrogen gas mixture by microwave plasma. Prior to gamma irradiation they were interfaced to proteins (fetal bovine serum) and cells (human sarcoma osteogenic cell line — SAOS2) in cell growth medium. Blank H-diamond SG-FETs did not degrade after the irradiation. With adsorbed proteins and cells they showed specific changes in gate current characteristics (about 100% increase) after the irradiation. These current changes are attributed to modified protein layer and cell morphology on the diamond surface. The presented results establish a first step towards real-time electronic monitoring of cell growth during the irradiation by therapeutically relevant doses.

Mitoxantrone-loaded superparamagnetic iron oxide nanoparticles as drug carriers for cancer therapy: Uptake and toxicity in primary human tubular epithelial cells

Superparamagnetic iron oxide nanoparticles (SPIONs) are in use for many clinical diagnostic and experimental therapeutic applications, for example, for targeted drug delivery. To analyze the cellular responses to mitoxantrone-carrying SPIONs (SPION-MTO), and to the drug released from SPIONs, we used an in vitro system that allows comparison of primary human cells with different endocytotic capacities, namely, epithelial cells from proximal and distal parts of the nephron. SPIONs were selectively and rapidly internalized by proximal tubular cells with high endocytotic potential, but not by distal tubular cells. Uptake did not affect cell viability or morphology. In both cell types, free MTO (10–100 nM) induced double-strand DNA breaks and senescence, cell hypertrophy and reduced cell proliferation. However, cadherin-mediated cell–cell adhesion, cytoskeletal structures or polarity of the cells were not affected. Interestingly, a comparable response was also observed upon treatment with SPION-MTO and was independent of uptake of the particles. The effect of SPION-MTO on cells which did not internalize particles was primarily related to the release of MTO from drug-coated particles upon incubation in serum-containing cell growth medium. In conclusion, we show that whereas the uptake of SPIONs does not affect cellular functions or viability, the toxicity of drug-loaded SPIONs depends essentially on the type of drug bound to nanoparticles. Due to the relatively low systemic toxicity of MTO, the effects of MTO-SPIONs on human tubular cells were moderate, but they may become clinically relevant when more nephrotoxic drugs are bound to SPIONs.

Transplantation of induced pluripotent stem cell-derived renal stem cells improved acute kidney injury.

BackgroundAcute kidney injury (AKI) is a severe disease with high morbidity and mortality. Methods that promote repair of the injured kidney have been extensively investigated. Cell-based therapy with mesenchymal stem cells or renal progenitor cells (RPCs) resident in the kidney has appeared to be an effective strategy for the treatment of AKI. Embryonic stem cells or induced pluripotent stem cells (iPSCs) are also utilized for AKI recovery. However, the therapeutic effect of iPSC-derived RPCs for AKI has yet to be determined.MethodsIn this study, we induced iPSCs differentiation into RPCs using a nephrogenic cocktail of factors combined with the renal epithelial cell growth medium. We then established the rat ischemia–reperfusion injury (IR) model and transplanted the iPSC-derived RPCs into the injured rats in combination with the hydrogel. Next, we examined the renal function-related markers and renal histology to assess the therapeutic effect of the injected cells. Moreover, we investigated the mechanism by which iPSC-derived RPCs affect AKI caused by IR.ResultsWe showed that the differentiation efficiency of iPSCs to RPCs increased when cultured with renal epithelial cell growth medium after stimulation with a nephrogenic cocktail of factors. The transplantation of iPSC-derived RPCs decreased the levels of biomarkers indicative of renal injury and attenuated the necrosis and apoptosis of renal tissues, but resulted in the up-regulation of renal tubules formation, cell proliferation, and the expression of pro-renal factors.ConclusionOur results revealed that iPSC-derived RPCs can protect AKI rat from renal function impairment and severe tubular injury by up-regulating the renal tubules formation, promoting cell proliferation, reducing apoptosis, and regulating the microenvironment in the injured kidney.Electronic supplementary materialThe online version of this article (doi:10.1186/s13578-015-0040-z) contains supplementary material, which is available to authorized users.

IgG Fc-binding peptide (FcBP)-tat conjugate as a smart antibody carrier into live cells

While use of RNA interference results in total loss of the target proteins, antibody binds to the corresponding epitope region but does not affect the expression level of the target protein. Consequently, it may offer opportunity to selectively evaluate biological function of selected domains from multi-domain proteins where each domain participates in its unique biological function. Although several methods for antibody transduction into live cells have emerged, most of them are suffered from harsh conditions or low delivery efficiency. In this study, we developed antibody transducer by conjugating IgG Fc-binding peptide (FcBP) with Tat, a cell penetrating peptide (CPP). FcBPCPP fusion peptide and FcBP-eGFP-Tat fusion protein, thus prepared, self-assembled to IgGs in situ upon their simple mixing in cell growth media, and translocated into the cytosol of live cells. Since FcBP-CPP reversibly binds to Fc-region of antibodies it neither impairs the structural and functional integrity of antibodies nor requires additional effort to modify antibodies. This represents the first synthetic peptide reagent, enabling antibody delivery into live cells in the absence of any additional detergents or other physical treatments such as electrophoresis or microinjection.

Abstract 185: MicroRNA-375 suppresses extracellular matrix degradation and invadopodial activity in head and neck squamous cell carcinoma

Abstract Head and neck squamous cell carcinoma (HNSCC) is a highly invasive cancer having an association with locoregional recurrence and lymph node metastasis. We previously reported that patients with lower microRNA-375 (miR-375) tumor:normal expression levels showed significantly decreased disease-specific survival, increased locoregional recurrence and distant metastasis. We also previously described that HNSCC cells with increased miR-375 showed significantly diminished invasion in vitro. The ability of cancer cells to degrade extracellular matrix (ECM) through secreted and membrane-bound proteases allows local invasion into the surrounding stroma, as well as possible metastasis. Invadopodia are specialized actin-rich structures, which mediate ECM degradation. Our objective was to determine whether elevated miR-375 expression in HNSCC cells also affects invadopodia formation and activity. For the evaluation of the matrix degradation properties of UMSCC1 and OSC19 cell lines, an invadopodial matrix degradation assay was used. Western blot analyses were conducted to measure the total protein levels of selected invadopodia-associated proteins. The tyrosine phosphorylation states of cortactin were evaluated by immunoprecipitation experiments. For the detection of levels of secreted proteases in the conditioned cell growth medium, Human Protease Arrays were used. Quantitative RT-PCR measurements were used to evaluate the mRNA expression levels of the commonly regulated proteases. We observed that the HNSCC cell lines with elevated miR-375 expression showed significant reductions in ECM degradation. We further identified that HNSCC cells expressing increased miR-375 expression had significantly suppressed amounts of mature invadopodia, although the levels of invadopodium precursors were not significantly altered. We determined that increased miR-375 expression in the HNSCC cell lines did not reduce cellular levels of invadopodia components, such as Tks5, cortactin and fascin. We also did not observe significant alterations to the tyrosine phosphorylation states of cortactin in the HNSCC cell lines. However, we found that the HNSCC cells with higher miR-375 expression had significant reductions in the mRNA expression and secreted levels of specific proteases, including Kallikrein 6, Kallikrein 10, and MMP-9. In summary, we have extended our understanding of the impact of miR-375 expression levels on HNSCC invasion. We demonstrated that increased miR-375 expression in HNSCC cells reduced ECM degradation and invadopodial activity. Our data suggest that reduced miR-375 expression in HNSCC patients can contribute to the invasive properties of head and neck cancer through increased invadopodial activity. Citation Format: Lizandra Jimenez, Ved P. Sharma, John S. Condeelis, Thomas M. Harris, Thomas J. Ow, Michael B. Prystowsky, Geoffrey J. Childs, Jeffrey E. Segall. MicroRNA-375 suppresses extracellular matrix degradation and invadopodial activity in head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 185. doi:10.1158/1538-7445.AM2015-185

Abstract 1388A: Assessment of the anti-angiogenic effect of VEGFR2 siRNA in HUVEC using the Lonza 4D-Nucleofecto system

Abstract Angiogenesis is a hallmark of most cancers, and is thus an attractive target for the treatment of cancer. One of the easiest screening and target validation strategies for anti-angiogenic target identification involves knocking down targets in Human Umbilical Vein Endothelial Cells (HUVEC) and assessing subsequent effects on tube formation in Corning's Matrigel product. The usage of small interfering RNA (siRNA) is one of the strategies to knock-down RNA, and thereby protein expression within cells. siRNA can be delivered within cells using either chemical transfection or electroporation-based strategies such as the one offered by the Lonza Nucleofector™ Technology. In the current study we used the Lonza 4D-Nucleofector™ X-Unit to transfect single-donor Clonetics™ HUVEC cultured in EGM™-2 Endothelial Cell Growth Media. Cells were transfected with siRNA directed against Vascular Endothelial Growth Factor Receptor 2 (VEGFR2). Transfection conditions were fine-tuned using pmaxGFP™ vector, and it was shown that the Nucleofection™ process had no deleterious effect on the tube formation potential of HUVEC on Corning's Matrigel product. Efficient knock-down of VEGFR2 protein levels was demonstrated after the transfection of VEGFR2-siRNA. Best knock-down efficiency was observed 24 hours after transfection. VEGFR2-siRNA transfected cells demonstrated significant inhibition of tube formation on Corning's Growth Factor Reduced Matrigel product in comparison to control samples. Since the efficient knock-down of the VEGFR2 protein in Clonetics™ HUVEC using the Nucleofector™ Technology can be demonstrated at time points as early as 24 hours after transfection, this is an efficient approach for target identification, validation and screening of siRNA based anti-angiogenesis therapeutics for cancer treatment. Citation Format: Srinivasan Kokatam, Kanchan Tiwari, Jenny Schroeder, Andrea Toell, Lubna Hussain, Preeti Kapoor. Assessment of the anti-angiogenic effect of VEGFR2 siRNA in HUVEC using the Lonza 4D-Nucleofecto system. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1388A. doi:10.1158/1538-7445.AM2015-1388A

Abstract 4672: Development of 2D - cell strain and 3D - tumor spheroid models for Precision Medicine

Abstract Background Precision oncology is a clinical approach aimed towards tailoring treatment strategies for patients based on the genetic profile of each patient's malignancy. Available cell line models are greatly limited in recapitulating the genetic profile of the tumor and tumor microenvironment of patients and therefore limit preclinical evaluation of new targeted agents. Furthermore, a high failure rate of drug candidates can be attributed in part to use of two dimensional (2D) monolayer cultures as the initial screening method that frequently produces inaccurate results and does not predict chemoresistance. The ability of three dimensional (3D) cultured tumor cells derived directly from patients to recapitulate tumor-like microenvironment suggests that engineered tumor models may provide more accurate and reproducible information for drug testing. At the Institute for Precision Medicine, we grow patient-derived 2D cell strains and engineer 3D tumor spheroids for patient`s tumor specific drug testing. Design Fresh tissue samples from 30 different solid tumors were digested in Type II or IV Collagenase (Gibco) and then re-suspended in growth factor reduced Matrigel (BD), plated on plastic, and overlaid with cell type specific cell growth media tsCM, which consists of either serum free Advanced DMEM/F12 (Gibco) with multiple growth factors optimized to propagate benign primary tumor cells, or FBS enriched DMEM/F12 media. Cultures were maintained at 37°C in 5% CO2. Once established, early cell strain culture passage and tumor spheroids size &amp;lt; 500 μm were cryopreserved. Specific drug testing was performed following 3 models: 2D monolayer culture, 2D monolayer culture converted in a 3D system using the hanging drop system from Biomatrix 3D®, and engineered 3D tumor spheroids. Results Our success rate in generating 2D- cell strains and 3D tumor spheroids is about 30%-40%. In the initial 30 samples, we were able to establish 11 continuous 2D and 3D tumor spheroid cultures derived from distinct primary and metastatic cancers including prostate, kidney, bladder and endometrium, as well as sarcomas and a neuroendocrine tumor. Tumor content in biopsy represents a major factor for successful growth. Histology and cytology examination demonstrates that 3D tumor spheroids recapitulate harvested tumors. Next generation sequencing shows the presence of same genomic alterations compared with original tumor without generating additional mutations. Conclusion We have developed individual patient-derived 2D tumor cell strains and 3D engineered tumor spheroids as well as models for patient`s tumor specific drug testing. This effort has been implemented for Precision Care and Clinical Trials at our Institution. Citation Format: Chantal Pauli, Jonathan Pauwels, Myriam Kossai, Nikolai Steklov, Andrea Sboner, Rema Rao, Kenneth Hennrick, Brian Robinson, Juan Miguel Mosquera, Himisha Beltran, Mark A. Rubin. Development of 2D - cell strain and 3D - tumor spheroid models for Precision Medicine. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4672. doi:10.1158/1538-7445.AM2015-4672

Sensitive and rapid detection of endogenous hydrogen sulfide distributing in different mouse viscera via a two-photon fluorescent probe

Development of efficient methods for detection of endogenous H2S in living cells and tissues is of considerable significance for better understanding the biological and pathological functions of H2S. Two-photon (TP) fluorescent probes are favorable as powerful molecular tools for studying physiological process due to its non-invasiveness, high spatiotemporal resolution and deep-tissues imaging. Up to date, several TP probes for intracellular H2S imaging have been designed, but real-time imaging of endogenous H2S-related biological processes in tissues is hampered due to low sensitivity, long response time and interference from other biothiols. To address this issue, we herein report a novel two-photon fluorescent probe (TPP-H2S) for highly sensitive and fast monitoring and imaging H2S levels in living cells and tissues. In the presence of H2S, it exhibits obviously improved sensitivity (LOD: 0.12 μM) and fast response time (about 2 min) compared with the reported two-photon H2S probes. With two-photon excitation, TPP-H2S displays high signal-to-noise ratio and sensitivity even no interference in cell growth media. As further application, TPP-H2S is applied for fast imaging of H2S in living cells and different fresh tissues by two-photon confocal microscope. Most importantly we first measured the endogenous H2S level in different viscera by vivisection and found that the distribution of endogenous H2S mostly in brain, liver and lung. The excellent sensing properties of TPP-H2S make it a practically useful tool for further studying biological roles of H2S.

Inhibitory role of reactive oxygen species in the differentiation of multipotent vascular stem cells into vascular smooth muscle cells in rats: a novel aspect of traditional culture of rat aortic smooth muscle cells.

Proliferative or synthetic vascular smooth muscle cells (VSMCs) are widely accepted to be mainly derived from the dedifferentiation or phenotypic modulation of mature contractile VSMCs, i.e., a phenotype switch from a normally quiescent and contractile type into a proliferative or synthetic form. However, this theory has been challenged by recent evidence that synthetic VSMCs predominantly originate instead from media-derived multipotent vascular stem cells (MVSCs). To test these hypotheses further, we re-examine whether the conventional rat aortic SMC (RASMC) culture involves the VSMC differentiation of MVSCs or the dedifferentiation of mature VSMCs and the potential mechanism for controlling the synthetic phenotype of RASMCs. We enzymatically isolated RASMCs and cultured the cells in both a regular growth medium (RGM) and a stem cell growth medium (SCGM). Regardless of culture conditions, only a small portion of freshly isolated RASMCs attaches, survives and grows slowly during the first 7days of primary culture, while expressing both SMC- and MVSC-specific markers. RGM-cultured cells undergo a process of synthetic SMC differentiation, whereas SCGM-cultured cells can be differentiated into not only synthetic SMCs but also other somatic cells. Notably, compared with the RGM-cultured differentiated RASMCs, the SCGM-cultured undifferentiated cells exhibit the phenotype of MVSCs and generate greater amounts of reactive oxygen species (ROS) that act as a negative regulator of differentiation into synthetic VSMCs. Knockdown of phospholipase A2, group 7 (Pla2g7) suppresses ROS formation in the MVSCs while enhancing SMC differentiation of MVSCs. These results suggest that cultured synthetic VSMCs can be derived from the SMC differentiation of MVSCs with ROS as a negative regulator.