For a list of peer-reviewed articles our products have been cited in, check out the publications page.
Please note that the general Technical Library page may contain additional product categories of interest.
The goal of personalized medicine is to stratify individual patients to the appropriate treatment. This approach depends on extensive characterization of individual tumors and their sensitivity to therapeutics. In the context of the immunotherapy of cancer, information on the localization, abundance and activation of immune cells within individual tumors gained in importance. Here we present a preclinical drug testing model to monitor individual drug responses of patients to targeted immunotherapy with the checkpoint inhibitor Nivolumab (anti- PD-1) and subsequent applications. In this study, we were able to determine different populations of infiltrating immune cells within viable tumors from colorectal cancer patients using our drug testing platform and a variety of subsequent applications.
Analysis of immune cells was conducted on disaggregated cells from viable tumor slices. Disaggregation of precision cut cancer tissue slices was performed using the GentleMACS from Miltenyi. Immune cell subsets were analyzed by flow cytometric multiplexing of CD3, CD4, CD8 and CD45. Furthermore, we identified PD-1 positive cells among the CD45+/CD3+ lymphocyte population, indicating relevance for anti-PD-1 targeted therapy in colorectal cancer. Presence and localization of immune cells (CD45+) was confirmed by immunohistochemistry of tumor tissue slices. In addition, protein expression of CD8 and PD-1 was analyzed by Simple Western Size analyses. Cytokine secretion affected by Nivolumab treatment was analyzed in supernatants of tissue cultures using the proinflammatory panel from Meso Scale Discovery. The results demonstrated that immune cell compositions were stable and uniform within our precision cut cancer tissue slices both pre- and post-cultivation, and pre- and post-treatment with Nivolumab.
Multiple myeloma has been comprehensively analyzed using high-throughput genomic technologies. Although a large number of biomarkers have been described, most of them were not subsequently validated at the protein level. In fact, the unresolved difficulties in studying the proteome have made the quantification of messenger RNA (mRNA) an indirect measure of protein expression. However, many studies have shown that levels of mRNA cannot be used as surrogates for protein levels. The amount of myeloma cells obtained after purification of patient samples is usually very limited, which precludes the possibility of quantify protein levels using standard Western Blot analysis.
AXL, a tyrosine kinase receptor, is expressed in a variety of cancers and has been revealed as the most highly expressed gene in preclinical models with acquired resistance, and second most common alteration in EGFR (epidermal growth factor receptor) inhibitor-resistant tumors, behind the T790M mutation. It has become obvious that targeted therapy of patients has to be monitored by taking and analyzing biopsies on a regular basis. Therefore, laboratory methods have to be adapted.
Congenital infection of human cytomegalovirus (HCMV) is one of the leading causes of non-genetic birth defects, and development of a prophylactic vaccine against HCMV is a top priority for public health. The gH/gL/pUL128-131 pentameric complex mediates HCMV entry into endothelial and epithelial cells, and it is a major target for neutralizing antibody responses. To better understand the mechanism by which antibodies interact with the epitopes of the gH/gL/pUL128-131 pentameric complex resulting in viral neutralization, we expressed and purified soluble gH/gL/pUL128-131 pentameric complex and gH/gL from Chinese hamster ovary cells. Our results highlight the importance of the gH/gL/pUL128-131 pentameric complex in HCMV vaccine design and emphasize the necessity to monitor the integrity of the pentameric complex during vaccine manufacturing process.
Mcl-1 is an anti-apoptotic member of the Bcl-2 family of proteins and is frequently amplified or over-expressed in both solid tumors and hematological malignancies, suggesting that its activity may be important for the survival of cancer cells. CDK9 inhibition results in the down regulation of Mcl-1 mRNA and subsequent protein levels by inhibiting transcription and represents an indirect approach to targeting Mcl-1. Mcl-1 can also be targeted directly using an inhibitor that disrupts the Mcl-1 complexes to induce apoptosis.
Amyotrophic lateral sclerosis (ALS) is a devastating and fatal neurodegenerative disease of adults which preferentially attacks the neuromotor system. It has been shown that Amyloid-beta (Aβ) levels are elevated in spinal cords of late-stage superoxide dismutase 1 (SOD1) G93A mice (model of familial amyotrophic lateral sclerosis [ALS]) and that Aβ peptide(s) were localized predominantly within affected motor neurons (MN) and surrounding glial cells. Moreover, neuromuscular junction (NMJ) loss and MN degeneration were reduced in SOD1 mice when APP was genetically ablated, suggesting that endogenous APP actively contributes to the pathophysiology of this form of ALS.
Additionally, Aβ and glutamate have been physiologically found in NMJs. Previous work done in our lab, showed the tight relationship between glutamate and Aβ in the NMJ. We showed that an interconnection between glutamate and Aβ peptide, as demonstrated in cortical and hippocampal neurons, is also operating in nerve-muscle co-cultures (Combes et al., 2015).
Here, using a nerve-muscle co-culture system, we studied the toxicity of Aβ and the mechanisms involved in the process of NMJ death. The aim of this study was to investigated the role and the mechanism of Aβ on an in vitro model of functional NMJ.
IRAK1 is a kinase which has been identified as a key regulator of cytokine signaling and is known to be involved in innate immune responses. Overexpression of these pleotropic cytokines have been implicated in various autoimmune diseases. Antagonists have shown clinical efficacy via modulation of various pro-inflammatory cytokine signals in various mouse models including the collagen induced arthritis (CIA) model. The identified project need was to demonstrate the engagement of IRAK1 with in-house chemical entities in-vitro by generating IC50s and ex-vivo using mouse tissue from the CIA model. To achieve this goal, a quantitative Capillary Western protein degradation assay was developed.
Alzheimer disease (AD) affects mainly people over the age of 65 years, suffering from different clinical symptoms such as progressive decline in memory, thinking, language, and learning capacity. The toxic role of beta amyloid peptide (Ab) has now shifted from insoluble Ab fibrils to smaller, soluble oligomeric Ab aggregates (AβO). Many evidences suggest that the neurodegenerative process would be due to the interaction of AβO with binding targets, activation of stress kinases, hyperphosphorylation of tau protein, caspase activation, loss of synapse, neuronal death, loss of cholinergic function, generation of reactive intermediates of oxygen (oxidative stress), or glutamate excitotoxicity. Urgent need for efficient new therapies is high, but could only be successful with an extensively comprehension of AβO degeneration process. In the present work, based on an in vitro primary cell culture treated with AβO preparation, we have carefully studied the cytopathological effects of AβO on neuronal death and then we have investigated the effect of 17-beta Estradiol (β-estr) on the degeneration process induced by AβO. Briefly we used rat cortical neurons (from E15). The cells were seeded in 96-well plates and intoxicated with AβO solution after 11 days of culture for 24 hours. β-estr was used at 100 nM (final concentration) and was added as pretreatment (1h before injuries). A co-incubation with selective inhibitors was performed for the mechanistic study. In parallel, western blotting (WB) analysis was done to quantify protein levels and their activation. We showed that β-estr was able to significantly protect neurons as well as glial cells from degeneration decreasing the caspase 3 activation and the massive mitochondrial stress (induced by AβO). Preservation of neurite network and synapsis integrity was also observed. Moreover, the large hyperphosphorylation of tau protein induced by AβO was significantly reduced with β-Estr. A mechanistic study was also performed co-incubating inhibitors of main survival pathways to try to better understand the mode of action of β-estr and the pathway involved in the AβO toxicity. We showed that the effects of -Estr were fully abolished blocking the MEK pathway as well as the DNA repair pathway (PARP-g) or the mitochondrial anti-apoptotic pathway (Bcl2). Interestingly the effect was inexisting coincubating β-estr with TrK receptor or Ras/Raf inhibitors showing the predominant role of growth factors paythway in its neuroprotective effect. Finally, we showed a large inactivation of AKT protein in presence of AβO that was reversed even over activated in presence of β-Estr.
Targeted anti-cancer therapy using small molecules or therapeutic antibodies is important to improve the treatment options of individual cancer patients whose tumor show specific expression patterns of respective target proteins. In order to enhance the development of new targeted drugs, novel and highly predictive in vitro drug testing models are needed which closely reflect the characteristics of each individual tumor.
Towards this end, Indivumed has developed a preclinical drug testing platform based on freshly cultivated tumor tissue slices which enables a detailed investigation of functional effects of classical chemotherapeutic drugs, small molecules and therapeutic antibodies in a natural tumor microenvironment. In addition, this multifunctional in vitro model permits the evaluation of target expression and analysis of signaling pathway activities.
The aim of the present study was to analyze and verify the functionality of an anti-EGFR antibody in colorectal cancer tissue slices using our recently developed drug testing platform. As readout of treatment effects changes in the expression and phosphorylation status of selected signaling proteins from two EGFR-related downstream pathways, the MAPK and Akt pathways, were evaluated by Meso Scale Discovery (MSD) assays and immunohistochemistry. To further analyze the complex regulation of phosphorylation pattern in more detail, we integrated the new NanoPro 1000 technology in our pathway analysis, enabling the identification of distinct isoform phosphorylations. This approach should help to extend the knowledge about individual drug responses among patients to further advance
The enzyme-drug L-asparaginase (L-ASP) has been used for four decades to treat acute lymphoblastic leukemia. However, its unique mechanism of action is still poorly understood, and its clinical efficacy has proven unpredictable. Those problems have prompted a continuing search for biomarkers that predict L-ASP response. We previously found that the expression of asparagine synthetase (ASNS) is strongly negatively correlated with L-ASP anticancer activity in ovarian cancer cell lines, suggesting that L-ASP might be effective against a low-ASNS subset of ovarian cancers if salient characteristics of the cell lines reflect clinical ovarian tumors. However, quantitatively robust, single-antibody assays for ASNS expression have been absent from the literature. We therefore used a capillary-based isoelectric focusing (IEF) platform (the NanoPro 1000) to screen twelve ASNS antibodies for their specificity and sensitivity. Only two antibodies exhibited completely on-target activity (as shown by signal ablation by ASNS siRNA) and sufficient sensitivity. The on-target activity corresponded to a single band on Western blot and a single peak on the NanoPro 1000, suggesting the existence of just one ASNS protein isoform. Optimized, final NanoPro assay conditions yielded less than 8% CV, a 160-fold dynamic range, and Z′-factor of 0.82, indicating a robust assay that is amenable to high-throughput screening. We next used the best ASNS antibody to develop an immunohistochemistry (IHC) assay for ASNS. As with the NanoPro assay, optimized IHC conditions yielded a large dynamic range of staining intensity, and staining was completely ablated by ASNS siRNA. To test the hypothesis that subsets of various cancer types express very low levels of ASNS, we have initiated ASNS IHC of more than 20 tissue arrays representing a wide variety of cancer types. Using a 3-point scoring system (0 = negative, 1 = low, 2 = high), among the tumor samples assayed, 90/136 (66%) of bladder cancer, 63/133 (47%) of bone cancer, 32/149 (22%) of breast cancer, 29/115 (25%) of brain cancer, 51/168 (30%) of colon cancer, 2/85 (2%) of endocrine system cancer, 23/99 (23%) of liver cancer, 7/64 (11%) of head and neck cancer, 7/136 (5%) of lung cancer, 13/53 (25%) of lymphoma, 1/25 (4%) of bone marrow lymphoma, 2/35 (6%) of lymphoma from spleen, 9/109 (8%) of melanoma, 81/396 (21%) of ovarian cancer, 3/29 (10%) of uterine cancer, 27/73 (37%) of pancreatic cancer, 5/119 (4%) of prostate cancer, 10/125 (8%) of renal cancer, 25/138 (18%) of testicular cancer, and 8/39 (21%) of thyroid cancer were ASNS-negative (score = 0), suggesting that a subset of each cancer type may be sensitive to the drug L-asparaginase. Efforts are underway to apply the NanoPro assay to the NCI-60 cell line panel and to continue performing ASNS IHC to survey tissue arrays for ASNS expression.
Background: Signaling from the IGF1R plays a role in resistance to anti‐cancer therapy in HNSCC. Thus, targeted inhibition of the IGF1R holds substantial therapeutic potential. While several inhibitors of the IGF1R are in clinical trials, there is no biomarker that predicts tumor responsiveness to anti-IGF1R therapy. Such a predictive biomarker is likely to be a component of the most prominent downstream signaling cascades from the IGF1R, which include the MEK/ERK or PI3K/AKT pathways that principally regulate proliferation and survival, respectively.
Hypothesis: Short‐term changes in the activation status of downstream signaling proteins will be predictive of long‐term tumor response to inhibitors of the IGF1R, and these changes will be detectable in minimal tissue samples using NIA technology.
Novel inhibitors of the hypoxia pathway [VEGF, PDGF] achieve response rates of 30-57% in renal cell carcinoma (RCC); yet threshold levels of targets and downstream signaling proteins have not been identified as biomarkers to guide treatment.
Methods: To profile hypoxia proteins in RCC clinical specimens, we have developed the use of automated nanoscale immunoassays for charge-based protein separation (NIA, NanoPro 1000) and charge-based
protein separation (Simple Western, Sally). To decrease the amount of tissue and invasive procedures required to obtain cells for analysis, we optimized assays to profile specimens acquired by fine needle aspiration (FNA).
Results: We used Simple Western to quantify proteins of the MAPK (ERK1, ERK2, pERK1, pERK2, MEK2), PI3K (S6, GSK3b, AKT2, pan-AKT) and STAT pathways (p-STAT5) and loading controls (tubulin, HSP-70) in more than 200 FNA's from solid tumors including RCC. Profiles can be completed overnight after receiving the specimen. Unique to NIA, we also analyzed percent phosphorylation and resolved differences in even a single phosphorylation in FNA specimens, allowing us to group tumors based upon different patterns of phosphorylation and percent phosphorylation.
Conclusions: Rapid and quantitative nanoproteomic profiling in very small amounts of clinical specimen is enabling translational studies for novel diagnostic and predictive biomarkers.
Aberrant expression and signaling in the EGF signaling cascade is a common occurrence in a variety of cancers including breast cancer. Understanding how EGF signaling impacts disease progression is key to the development of novel therapeutics. Analysis of ERK1/2 and 4E-BP1 expression in cancer samples frequently employs Western blot analysis. In-depth phosphorylation analysis often requires 2D gels which are extremely variable and labor intensive, followed by MS analysis. In this study, novel, capillary-based technologies by ProteinSimple are used to evaluate changes in signaling proteins. Size-based as well as charge-based separation techniques were utilized, each of which is followed by immunoassay detection.
Size-based characterization of proteins has been predominately performed by either SDS-PAGE/Western blot analysis or by capillary electrophoresis (CE). Each technique has advantages – Western blotting exploits high sensitivity as well as specificity of antibody binding, and CE offers high resolution and reproducibility. The sensitivity and resolution of the results obtained from either method is often challenged by the ability to preconcentrate or stack enough protein sample before separation. Simon, a new size-based separation platform that runs Simple Western assays, combines for the first time the advantages of both Western blotting and CE into a single automated workflow. The work presented illustrates the dependency of stacking efficiency upon the plug length of the sample and stacking matrix. Optimization of stacking conditions resulted in a significant sensitivity and resolution increase using the Simple Western assay.
We present data comparing analysis of key targets of the AKT signaling cascade via Western blot and Simple Western on Simon, highlighting workflow, biological response, sensitivity, and resolution.
Application of a novel nano-immunoassay platform to assess changes in cIAP1 in response to the SMAC-mimetic, LCL161
We present the development of novel nanoimmunoassays for the translational repressor proteins 4E-BP1 and 4E-BP2 using NanoPro technology. Both the PI3 kinase/Akt pathway and FRAP/mTOR kinase pathway regulate 4E-BP1 activity, making 4E-BP1 a focal point for these two important signaling pathways. 4E-BP2 regulation is poorly understood, partially due to the lack of specific anti-phospho 4E-BP2 antibodies. Our assay, developed on the Cell Biosciences NanoPro platform, enables detailed differential investigation of 4E-BP1 and 4E-BP2 phosphorylation and signal transduction.
Here we describe a precise screening assay that quantifies changes in phosphorylation of proteins in samples from as few as 100 cells, which is simple, rapid, and relatively low in cost. A nano-immunoassay system (Cell Biosciences) was used to measure changes in expression and activation of relevant signaling proteins, including MEK, ERK and STATs in U937 monocyte cells before and after cytokine treatment. A single pan-specific antibody was used to distinguish between the phosphorylated and non-phosphorylated protein isoforms, as the nano-immunoassay (NIA) method separates different phosphorylated forms of a protein based on their isoelectric point. In parallel, phospho-protein FACS analysis, which is the current state of the art for measuring multiple signaling pathways, was performed to compare changes in expression and phosphorylation of the signaling proteins. Phospho-protein FACS analysis is expensive and requires considerable technical expertise, which limits its application for large numbers of samples. This novel nano-immunoassay screening method is currently being employed at the Stanford Human Immune Monitoring Core (HIMC) and is being used for high-throughput screening of compounds that influence monocyte activation, monocyte/macrophage differentiation and analysis of various disease states in small primary tissue samples. Practical examples will be given.
To fully enable the vision of 'bench-to-bedside' requires the development of not only novel therapies, but novel techniques for evaluating their efficacy in cell lines, animal models and primary tumor material. This report describes our development of a technique employing a nanoimmunoassay platform for the analysis of signaling protein activation in primary non-small lunch cancer (NSCLC) solid tumors.
Cell Biosciences' novel nano-immunoassay screening method is being adopted in an ever-increasing range of institutions, thanks to an innovative collaborative effort collaborative effort between Stanford's Human Immune Monitoring Core (HIMC), Comprehensive Cancer Center, and Cell Biosciences.
The precise screening assay quantifies changes in phosphorylated and non-phosphorylated protein isoforms in tiny samples. Notably, the assays are simple, rapid, and relatively low in cost.
The centralized location of the instrument, and unique collaborative environment have enabled rapid development and adoption of Firefly assays - first within Stanford, and now extending to other institutions, both academic and commercial.
Activation of the MAPK pathway involves a complicated web of MEK phosphorylations. The two MEK isoforms are regulated by at least 3 other enzymes — PAK, RAF and ERK. Up until now it has been impossible to quantitate and determine the stoichiometry of the various multiply phosphorylated MEK forms. We have developed a new capillary immunoassay which resolves the different MEK variants, and allows measurement of the relative abundance of each form with a single antibody. This measurement of how the multiply phosphorylated forms change gives insight into how the dynamics of pathway feedback and activity change in response to drug treatment.
We have shown that signaling upstream of MEK kinase is inhibited by negative feedback in tumor cells in which the pathway is driven by HER kinases. In these cells, MEK1 is phosphorylated at ERK-- and PAK-dependent sites (T292, S298), whereas phosphorylation on RAF-dependent sites is undetectable. A selective MEK inhibitor inhibits ERK phosphorylation, relieves the negative feedback and activates MEK phosphorylation in these cells. Under these conditions, phosphorylation of both kinases on the RAF dependent sites (S217, S222) is markedly induced. Thus, inhibition of MEK/MAPK signaling in these cells abrogates upstream feedback of the pathway and results in a complex change in phosphorylation of MEK due to multiple kinases.
The capillary immunoassay allows determination of complex changes in phosphorylation of MEK kinase by PAK, RAF and ERK kinases in response to MEK inhibition. This technique will be useful in mapping pathway network response to targeted drugs in vitro and in vivo.
Oncoprotein quantification in clinical specimens is important for the diagnosis of specific hematopoietic malignancies as well as the development and monitoring of effective therapies that target oncoproteins. Current protein detection methods require large samples, precluding routine serial tumor sampling to assess changes in oncoprotein levels. Here we demonstrate the use of a nano-immunoassay system (Firefly™ system) to distinguish between patient specimens of Burkitt's vs. Follicular lymphoma by characterizing patterns of MYC and BCL2 expression. Changes in the expression and activation of a variety of onco/signaling proteins including ERK, MEK, STAT and JNK in malignant hematopoietic (CML) cells and patient samples before and after treatment with therapeutic agents that impact oncogenic signaling pathways are also shown. The expression levels of the different proteins were measured with high sensitivity in samples as small as 400 cells. A key benefit of this technology is that it separates protein isoforms based on its isoelectric point. Using this assay, we were able to distinguish and quantify the phosphorylated and non-phosphorylated forms of each protein with a single antibody. Thus, we have developed a novel technique which can precisely evaluate the activity levels of signaling proteins in oncogenic pathways from very small samples.
A recent wave of anti-cancer compounds that target tyrosine kinases (TKIs) has been moving through the drug development pipeline. Assessment and screening of lead compounds in simple model systems is relatively straight forward. Until recently, however, determining the impact of these compounds in complex biology of patient-derived cells and tissues has been diffcult. Proposed genetic or protein biomarkers can act as surrogates to a response, but measuring the signaling pathway in both the target cells and surrounding normal tissue will provide a more direct metric. This has proven diffcult due to the limited nature of primary material and complexity of tissue structure. Here we describe a novel nano-immunoassay platform (Firefly™) that has two significant advantages over traditional immunoassays: (1) extremely sensitive protein detection, and (2) physical isoform separation, which allows for quantitation of protein isoforms as well as post-translational modifications such as phosphorylation.
Applications of this technology that will be described include:
1. Effect of TKIs on signaling in punch biopsies of non-small cell lung cancer cells
2. Signaling pathway response from chronic myleogenous leukemia patients to therapies targeted to the bcr/abl translocation
The discovery of tumor stem cells in acute myeloid leukemia a decade ago initiated a field of research has accelerated growth in the past few years. Researchers are now describing tumor stem cells in a variety of hematopoietic and solid tumors. The impetus for much of this research is the desire to identify targets for drug intervention in these critical tumor populations. The molecular pathways that functionally define these cells are important therapeutic targets. Tumor stem cells are rare and provide insufficient material to use standard assay methods. Although DNA microarray and/or qPCR are used to study tumor stem cells, their rare nature limits quantitative protein analysis. This creates a gap in our knowledge since many proteins, such as beta-catenin or MAPK signaling proteins, are not regulated at the transcriptional level, but through post-translational modifications (phosphorylation, ubiquitination, etc.). Here we describe a technique utilizing a nanoimmunoassay platform (Firefly?) to measure tumor stem cell proteins. Transitional tumor stem cells (TCC+) were sorted from a patient tumor and lysed for analysis. A lysate of 400 cells was subjected to isoelectric focusing and immobilization. Immunodetection was performed and quantitation of signal was measured using HRP-labeled secondary chemiluminescence reagents. Here we report beta-catenin protein concentrations of 192 ng/mg of total protein in the tumor stem cells, which was undetectable in 'non-stem' tumor cells. Comparisons of protein levels and the degree of phosphorylation are made between these samples, other tumor cell lines and hematopoetic stem cells.