High expression of both desmoplastic stroma and epithelial to mesenchymal transition markers associate with shorter survival in pancreatic ductal adenocarcinoma

Desmoplastic stroma (DS) and the epithelial-to-mesenchymal transition (EMT) play a key role in pancreatic ductal adenocarcinoma (PDAC) progression. To date, however, the combined expression of DS and EMT markers, and their association with variations in survival within each clinical stage and degree of tumor differentiation is unknown. The purpose of this study was to investigate the association between expression of DS and EMT markers and survival variability in patients diagnosed with PDAC. We examined the expression levels of DS markers alpha smooth muscle actin (α-SMA), fibronectin, and vimentin, and the EMT markers epithelial cell adhesion molecule (EPCAM), pan-cytokeratin, and vimentin, by immunohistochemistry using a tissue microarray in a retrospective cohort of 25 patients with PDAC. The results were examined for association with survival by clinical stage and by degree of tumor differentiation. High expression of DS markers -α-SMA, fibronectin, and vimentin- was associated with decreased survival at intermediate and advanced clinical stages (p=0.006-0.03), as well as with both poorly and moderately differentiated tumor grades (p=0.01-0.02). Interestingly, the same pattern was observed for EMT markers, i.e., EPCAM, pan-cytokeratin, and vimentin (p=0.00008-0.03). High expression of DS and EMT markers within each clinical stage and degree of tumor differentiation was associated with lower PDAC survival. Evaluation of these markers may have a prognostic impact on survival time variation in patients with PDAC.

Reporter gene systems for the identification and characterization of cancer stem cells

Cancer stem cells (CSCs) are tumor cells that share functional characteristics with normal and embryonic stem cells. CSCs have increased tumor-initiating capacity and metastatic potential and lower sensitivity to chemo- and radiotherapy, with important roles in tumor progression and the response to therapy. Thus, a current goal of cancer research is to eliminate CSCs, necessitating an adequate phenotypic and functional characterization of CSCs. Strategies have been developed to identify, enrich, and track CSCs, many of which distinguish CSCs by evaluating the expression of surface markers, the initiation of specific signaling pathways, and the activation of master transcription factors that control stemness in normal cells. We review and discuss the use of reporter gene systems for identifying CSCs. Reporters that are under the control of aldehyde dehydrogenase 1A1, CD133, Notch, Nanog homeobox, Sex-determining region Y-box 2, and POU class 5 homeobox can be used to identify CSCs in many tumor types, track cells in real time, and screen for drugs. Thus, reporter gene systems, in combination with in vitro and in vivo functional assays, can assess changes in the CSCs pool. We present relevant examples of these systems in the evaluation of experimental CSCs-targeting therapeutics, demonstrating their value in CSCs research.

Benchmark of Generic Shapes for Macrocycles

Macrocycles target proteins that are otherwise considered undruggable because of a lack of hydrophobic cavities and the presence of extended featureless surfaces. Increasing efforts by computational chemists have developed effective software to overcome the restrictions of torsional and conformational freedom that arise as a consequence of macrocyclization. Moloc is an efficient algorithm, with an emphasis on high interactivity, and has been constantly updated since 1986 by drug designers and crystallographers of the Roche biostructural community. In this work, we have benchmarked the shape-guided algorithm using a dataset of 208 macrocycles, carefully selected on the basis of structural complexity. We have quantified the accuracy, diversity, speed, exhaustiveness, and sampling efficiency in an automated fashion and we compared them with four commercial (Prime, MacroModel, molecular operating environment, and molecular dynamics) and four open-access (experimental-torsion distance geometry with additional “basic knowledge” alone and with Merck molecular force field minimization or universal force field minimization, Cambridge Crystallographic Data Centre conformer generator, and conformator) packages. With three-quarters of the database processed below the threshold of high ring accuracy, Moloc was identified as having the highest sampling efficiency and exhaustiveness without producing thousands of conformations, random ring splitting into two half-loops, and possibility to interactively produce globular or flat conformations with diversity similar to Prime, MacroModel, and molecular dynamics. The algorithm and the Python scripts for full automatization of these parameters are freely available for academic use.

Taking advantage of a high-throughput flow cytometer for the implementation of an ADCC assay for regulatory compliance

•

High-throughput flow cytometry for the evaluation of ADCC potency.

•

Optimization of biological assays for batch release testing of biopharmaceuticals.

•

Quickly turn multi-parameter acquisition by flow cytometry.

Technological advances allowed the development of high-throughput instruments such as IntelliCyt iQue Screener PLUS®. Here, we took advantage of this technology to transfer a previously validated cytotoxicity assay. The evaluated parameters were cell permeability, caspase activation and phosphatidyl serine exposure. The assay was accurate (r² = 0.90), precise (%CV ≤ 18.90) and specific. These results showed that this technology is suitable to be used in control quality environments. In addition, the automation provided a faster acquisition and analysis of data with precise and accurate results. This application could be implemented to evaluate another in vitro mechanism of action of different biotherapeutics.

Development and validation of a mass spectrometric method to determine the identity of rituximab based on its microheterogeneity profile

Analytical methods have been considered the "eyes" for development, characterization and batch releasing of biotherapeutics over the past 40 years. One of the most powerful analytical platform for biotherapeutic analysis is mass spectrometry coupled to liquid chromatography (LC-MS). Due to its wide flexibility and instrumental configurations, LC-MS can determine different physicochemical attributes of proteins, e.g. molecular mass, primary sequence, and posttranslational modifications. Intact molecular mass analysis of therapeutic proteins is essential to confirm their identity. Analytical methods must be validated to support drug quality information during its approval process. Although there are international guidelines that provide general information on validation of analytical methods, practical examples about the design, selection of validation attributes and acceptance criteria of identity LC-MS methods are scarce. Here, according to the recommendations of Q2R1 ICH guideline, we showcase the validation of an LC-MS-TOF method to identity rituximab by determining its intact and deglycosylated molecular mass profiles. The proposed method specifically identified the m/z profile and deconvoluted mass profile of rituximab from deglycosylated rituximab and from excipient blank (specificity) with a maximum error of 76.63 ppm (accuracy) and a maximum Relative Standard Deviation (RSD) of 0.00315% (precision). Besides, the system suitability test, which was based on the expected mass value of the mass calibrator, confirmed the reliability of the analytical results. In summary, validation showed that the proposed method is suitable for identifying rituximab based on its glycosylated (intact) and deglycosylated mass profile.

Validation of a Cell Proliferation Assay to Assess the Potency of a Dialyzable Leukocyte Extract Intended for Batch Release

Transferon^® is a blood product with immunomodulatory properties constituted by a complex mixture of peptides obtained from a human dialyzable leukocyte extract (DLE). Due to its complex nature, it is necessary to demonstrate batch consistency in its biological activity. Potency is the quantitative measure of biological activity and is also a quality attribute of drugs. Here we developed and validated a proliferation assay using Jurkat cells exposed to azathioprine, which is intended to determine the potency of Transferon^® according to international guidelines for pharmaceuticals. The assay showed a linear response (2.5 to 40 µg/mL), coefficients of variation from 0.7 to 13.6% demonstrated that the method is precise, while r² = 0.97 between the nominal and measured values obtained from dilutional linearity showed that the method is accurate. We also demonstrated that the cell proliferation response was specific for Transferon^® and was not induced by its vehicle nor by other peptide complex mixtures (glatiramer acetate or hydrolyzed collagen). The bioassay validated here was used to assess the relative potency of eight released batches of Transferon^® with respect to a reference standard, showing consistent results. The collective information from the validation and the assessment of several batches indicate that the bioassay is suitable for the release of Transferon^®.

Determination of Peptide Profile Consistency and Safety of Collagen Hydrolysates as Quality Attributes

Abstract

Collagen hydrolysates are dietary supplements used for nutritional and medical purposes. They are complex mixtures of low‐molecular‐weight peptides obtained from the enzymatic hydrolysis of collagen, which provide intrinsic batch‐to‐batch heterogeneity. In consequence, the quality of these products, which is related to the reproducibility of their mass distribution pattern, should be addressed. Here, we propose an analytical approach to determine the peptide pattern as a quality attribute of Colagenart®, a product containing collagen hydrolysate. In addition, we evaluated the safety by measuring the viability of two cell lines exposed to the product. The consistency of peptide distribution was determined using Size Exclusion Chromatography (SEC), Mass Spectrometry coupled to a reversed phase UPLC system (MS‐RP‐UPLC), and Shaped‐pulse off‐resonance water‐presaturation proton nuclear magnetic resonance spectrometry [¹Hwater_presat NMR]. The mass distribution pattern determined by SEC was in a range from 1.35 to 17 kDa, and from 2 to 14 kDa by MS‐RP‐UPLC. [¹Hwater_presat NMR] showed the detailed spin‐systems of the collagen hydrolysates components by global assignment of backbone Hα and NH, as well as side‐chain proton resonances. Additionally, short‐range intraresidue connectivity pathways of identified spin‐regions were obtained by a 2D homonuclear shift correlation Shaped‐pulse solvent suppression COSY scheme. Safety analysis of Colagenart® was evaluated in CaCo‐2 and HepG2 cells at 2.5 and 25 μg/mL and no negative effects were observed. The results demonstrated batch‐to‐batch reproducibility, which evinces the utility of this approach to establish the consistency of the quality attributes of collagen hydrolysates.

Practical Application

We propose state‐of‐the art analytical methodologies (SEC, MS, and NMR) to evaluate peptide profile and composition of collagen hydrolysates as quality attributes. These methodologies are suitable to be implemented for quality control purposes.

Development and validation of a bioassay to evaluate binding of adalimumab to cell membrane-anchored TNFα using flow cytometry detection

Physicochemical and structural properties of proteins used as active pharmaceutical ingredients of biopharmaceuticals are determinant to carry out their biological activity. In this regard, the assays intended to evaluate functionality of biopharmaceuticals provide confirmatory evidence that they contain the appropriate physicochemical properties and structural conformation. The validation of the methodologies used for the assessment of critical quality attributes of biopharmaceuticals is a key requirement for manufacturing under GMP environments. Herein we present the development and validation of a flow cytometry-based methodology for the evaluation of adalimumab's affinity towards membrane-bound TNFα (mTNFα) on recombinant CHO cells. This in vitro methodology measures the interaction between an in-solution antibody and its target molecule onto the cell surface through a fluorescent signal. The characteristics evaluated during the validation exercise showed that this methodology is suitable for its intended purpose. The assay demonstrated to be accurate (r² = 0.92, slope = 1.20), precise (%CV ≤ 18.31) and specific (curve fitting, r² = 0.986-0.997) to evaluate binding of adalimumab to mTNFα. The results obtained here provide evidence that detection by flow cytometry is a viable alternative for bioassays used in the pharmaceutical industry. In addition, this methodology could be standardized for the evaluation of other biomolecules acting through the same mechanism of action.

Abstract P3-06-09: Selection of presumed CD49f antagonists and their biological evaluation in breast cancer cells

Breast cancer is the second cause of cancer death in women and the large majority of those deaths are due to drug resistance and/or recurrence. The cancer stem cell (CSC) model suggests that tumor stem-like cells play key roles in resistance and recurrence in breast cancer patients. Thus, CSCs have been pointed as targets for new anti-cancer therapies. CD49f is an integrin subunit that participates in the CSC-niche interaction. Knock-down of CD49f in breast cancer cells impairs mammosphere formation in vitro and tumorigenesis in vivo, suggesting that this protein is needed for maintenance of stemness.

Aiming to target breast CSC, we used consensus docking to select potential CD49f antagonists from a collection of 13,000+ drugs with previous clinical evaluations. Seven compounds with the lowest consensus Z score were selected for in vitro biological validation. Cell adhesion assays showed that four of the selected drugs (5193, 1382, 7631, and 12723) decrease the binding of CD49f+ MDA-MB-231 breast cancer cells to laminin, suggesting that those compounds antagonize the receptor. Mammosphere formation assays showed that compounds 5193, 1382, and 12723 limit the clonogenic capability of CD49f+ breast cancer cells in vitro. Compound 5193 was highly toxic in 2D cell viability assays. On the other hand, the clonogenic impairment produced by compounds 1382 and 12723 is independent of bulk cell line cytotoxicity, suggesting a direct impact on the CSC pool. The analyses of the effect of these drugs on the expression of breast CSC markers and CD49f-activated pathways are on their way.

Thus, we have identified some drugs that might be repurposed to target breast CSC. Since the pharmacokinetics and toxicology of those drugs is known, they could easily be ready for clinical trials. We demonstrated that in silico screening is useful to identify antagonists of receptors with relevant roles in breast CSC biology.

This work was supported by CONACYT 221105, PAPIIT-UNAM IN228616, and Red temática de células troncales y medicina regenerativa.

Citation Format: Velasco-Velázquez M, Velázquez-Quesada I, Aguirre-Alvarado C, Guerrero-Rodríguez S, Ruiz-Moreno A, Ramirez-Salinas G, Segura-Cabrera A, Pérez-Tapia M. Selection of presumed CD49f antagonists and their biological evaluation in breast cancer cells [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-06-09.

Abstract B10: Cyclin D1 restrains oncogene-induced autophagy via phosphorylation of LKB1

Cyclin D1 is an important molecular driver of many human cancers. The cyclin D1 gene is amplified or overexpressed in up to half of human breast cancers and mammary-targeted overexpression of cyclin D1 is sufficient to induce mammary tumorigenesis in mice. Cyclin D1 encodes the regulatory subunit of the cyclin-dependent kinase (CDK) holoenzyme that phosphorylates several substrates including the retinoblastoma protein (pRb) to advance the G1S cell cycle checkpoint and promote DNA synthesis. Recent studies have implicated cell cycle regulators that govern G1S transition, in regulating cellular metabolism. Cyclin D1 phosphorylates and inactivates a nuclear encoded protein essential for mitochondrial biogenesis, Nrf1. In this manner cyclin D1 coordinates both nuclear and mitochondrial functions. Consistent with cyclin D1-dependent inhibition of mitochondrial biogenesis, pRB promotes and E2F-1 inhibits mitochondrial biogenesis. In addition to inhibiting mitochondrial biogenesis, cyclin D1 inhibits mitochondrial membrane potential, which may be in part due to binding VDAC.

Autophagy is a catabolic pathway activated in response to cellular stress such as oxidative or nutritional stress. It mitigates cellular damage via removal of insoluble and damaged proteins, lipids and organelles. Autophagy is enhanced by the phosphorylated and activated form of 5’-AMP-activated protein kinase (AMPK). We initiated the following study to directly test the effect of cyclin D1 has on cellular metabolism and autophagy. Herein, endogenous cyclin D1 restrained autophagy in breast cancer cells in tissue culture and in the mammary gland of mice. Using mammary epithelial-targeted deletion of cyclin D1 we show cyclin D1 restrains autophagy by reducing AMPK activation. Cyclin D1 may serve to couple cellular proliferation to cellular energy homeostasis.

Citation Format: Mathew Casimiro, Gabriele Di Sante, Emanuele Loro, Timothy Pestell, Sara Bisetto, Marco Velasco-Velázquez, Xuanmao Jiao, Zhiping Li, Chenguang Wang, Daniel Ly, Bin Zheng, Shen Che-Hung, Adam Ertel, Richard G. Pestell. Cyclin D1 restrains oncogene-induced autophagy via phosphorylation of LKB1. [abstract]. In: Proceedings of the Fourth AACR International Conference on Frontiers in Basic Cancer Research; 2015 Oct 23-26; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2016;76(3 Suppl):Abstract nr B10.

Swine Dialyzable Spleen Extract as Antiviral Prophylaxis

Worldwide, the most highly consumed meat is of porcine origin. The production and distribution of swine meat are affected by diverse health matters, such as influenza and diarrhea, which cause head losses and require the use of antibiotics and other drugs in hog farms. To stimulate newborn piglet immune responses and increase resistance to infections, we developed a spray-drying technique to produce dried swine dialyzable spleen extract (sDSE), an immunomodulator. Based on the size-exclusion ultra performance liquid chromatography quantitative analysis, it was possible to recover up to 58% of the product after the drying process. The biological activity of orally administered dried sDSE increased mouse survival and induced cytokine production in a herpes infection model.

The CCL5/CCR5 axis promotes metastasis in basal breast cancer

Recently, we have shown that the CCL5/CCR5 axis is active in patients affected by an aggressive basal subtype of breast cancer. Using preclinical models, we have demonstrated that CCR5 promotes breast cancer invasiveness and metastatic potential, while CCR5 inhibition abrogates them. Thus, CCR5 antagonists may constitute an alternative therapeutic approach for patients affected by metastatic basal breast cancer.

Biological activity of dialyzable leukocyte extracts in a mouse cutaneous herpes model. (VAC6P.946)

Human dialyzable leukocyte extracts (DLE) are heterogeneous mixtures of low-molecular-weight peptides. DLE improve the clinical responses in infections, allergies, cancer, and immunodeficiencies. TransferonTM is a human DLE registered as a drug by Mexican health authorities and commercialized nationally. In order to establish a model that could be used routinely to assess the activity of TransferonTM, we standardized and validated a mouse model of HSV-1 cutaneous infection. In such model, we evaluated the biological activity of 27 TransferonTM batches that complied with other quality standards. All batches improved survival of HSV-1-infected mice; average survival increased from 20.9% in control mice to 59.6% in TransferonTM-treated mice. Biological activity of TransferonTM correlated with increased serum levels of IFN-γ and reduced IL-6 and TNF-α concentrations at 7-9 days post-infection (high mice mortality period). Our results show that: a) the mouse cutaneous herpes model allows the evaluation of the biological activity of TransferonTM; b) the assay can be used as a routine tests for batch release; c) TransferonTM is produced with high homogeneity between batches; and d) the protective effect of TransferonTM in this model correlates with differential changes in cytokines related to innate or adaptive immunity, suggesting that immunomodulation is associated to the reported therapeutic effects on herpes infections. Supported by FTU/IB/012/010/PRO.

Overview of cyclins D1 function in cancer and the CDK inhibitor landscape: past and present

INTRODUCTION

Intensive efforts, over the last decade, have been made to inhibit the kinase activity of cyclins that act as mediators during cell-cycle progression. Activation of the cyclin D1 oncogene, often by amplification or rearrangement, is a major driver of multiple types of human tumors including breast and squamous cell cancers, B-cell lymphoma, myeloma and parathyroid adenoma.

AREAS COVERED

In this review, the authors summarize the activity of cyclins and cyclin-dependent kinases in cell-cycle progression and transcription. They focus on cyclin D1/CDK4/CDK6, a central mediator in the transition from G1 to S phase. Furthermore, the authors discuss the first generation of pan-cyclin-dependent kinase inhibitors that failed to meet expectation and discuss, in detail, the second generation of highly specific cyclin D1/CDK4/CDK6 inhibitors that are proving to be more efficacious.

EXPERT OPINION

The mechanism by which cyclin D1 drives tumorigenesis may be dependent on kinase and kinase-independent functions. Further evidence is necessary to delineate the roles of cyclin D1 in early pre-neoplastic lesions where its overexpression may promote genomic instability in a kinase-independent manner.

Batch-to-batch reproducibility of Transferon™

Human dialyzable leukocyte extracts (DLEs) are heterogeneous mixtures of low-molecular-weight peptides that modulate immune responses in various diseases. Due their complexity, standardized methods to identify their physicochemical properties and determine that production batches are biologically active must be established. We aimed to develop and validate a size exclusion ultra performance chromatographic (SE-UPLC) method to characterize Transferon™, a DLE that is produced under good manufacturing practices (GMPs). We analyzed an internal human DLE standard and 10 representative batches of Transferon™, all of which had a chromatographic profile characterized by 8 main peaks and a molecular weight range between 17.0 and 0.2kDa. There was high homogeneity between batches with regard to retention times and area percentages, varying by less than 0.2% and 30%, respectively, and the control chart was within 3 standard deviations. To analyze the biological activity of the batches, we studied the ability of Transferon™ to stimulate IFN-γ production in vitro. Transferon™ consistently induced IFN-γ production in Jurkat cells, demonstrating that this method can be included as a quality control step in releasing Transferon™ batches. Because all analyzed batches complied with the quality attributes that were evaluated, we conclude that the DLE Transferon™ is produced with high homogeneity.

CCR5 antagonist blocks metastasis of basal breast cancer cells

The roles of the chemokine CCL5 and its receptor CCR5 in breast cancer progression remain unclear. Here, we conducted microarray analysis on 2,254 human breast cancer specimens and found increased expression of CCL5 and its receptor CCR5, but not CCR3, in the basal and HER-2 genetic subtypes. The subpopulation of human breast cancer cell lines found to express CCR5 displayed a functional response to CCL5. In addition, oncogene transformation induced CCR5 expression, and the subpopulation of cells that expressed functional CCR5 also displayed increased invasiveness. The CCR5 antagonists maraviroc or vicriviroc, developed to block CCR5 HIV coreceptor function, reduced in vitro invasion of basal breast cancer cells without affecting cell proliferation or viability, and maraviroc decreased pulmonary metastasis in a preclinical mouse model of breast cancer. Taken together, our findings provide evidence for the key role of CCL5/CCR5 in the invasiveness of basal breast cancer cells and suggest that CCR5 antagonists may be used as an adjuvant therapy to reduce the risk of metastasis in patients with the basal breast cancer subtype.

Gram-negative bacteria and phagocytic cell interaction mediated by complement receptor 3

Complement receptor 3 (CR3) is an integrin that recognizes several different ligands. Binding to CR3 in phagocytic cells activates signaling pathways involved in cytoskeleton rearrangement, regulation of cell motility, alteration of gene expression and phagocytosis of complement-opsonized as well as of some non-opsonized particles and pathogenic bacteria. However, CR3-mediated phagocytosis of some Gram-negative bacteria does not induce bacterial clearance. Pseudomonas aeruginosa, Salmonella and Escherichia coli are eliminated after phagocytic cell-bacteria interaction mediated by CR3. However, Bordetella takes advantage of the CR3 function and uses it to enter into macrophages leading to bacterial survival. The final fate of the pathogen is determined by combinations of host and bacterial factors, in which molecular interactions between CR3 and bacterial ligands are involved.