3D collagen type I matrix inhibits the antimigratory effect of doxorubicin

Colorectal Cancer Cell Invasion and Functional Properties Depend on Peri-Tumoral Extracellular Matrix

We investigated how the extracellular matrix (ECM) affects LoVo colorectal cancer cells behavior during a spatiotemporal invasion. Epithelial-to-mesenchymal transition (EMT) markers, matrix-degrading enzymes, and morphological phenotypes expressed by LoVo-S (doxorubicin-sensitive) and higher aggressive LoVo-R (doxorubicin-resistant) were evaluated in cells cultured for 3 and 24 h on Millipore filters covered by Matrigel, mimicking the basement membrane, or type I Collagen reproducing a desmoplastic lamina propria. EMT and invasiveness were investigated with RT-qPCR, Western blot, and scanning electron microscopy. As time went by, most gene expressions decreased, but in type I Collagen samples, a strong reduction and high increase in MMP-2 expression in LoVo-S and -R cells occurred, respectively. These data were confirmed by the development of an epithelial morphological phenotype in LoVo-S and invading phenotypes with invadopodia in LoVo-R cells as well as by protein-level analysis. We suggest that the duration of culturing and type of substrate influence the morphological phenotype and aggressiveness of both these cell types differently. In particular, the type I collagen meshwork, consisting of large fibrils confining inter fibrillar micropores, affects the two cell types differently. It attenuates drug-sensitive LoVo-S cell aggressiveness but improves a proteolytic invasion in drug-resistant LoVo-R cells as time goes by. Experimental studies on CRC cells should examine the peri-tumoral ECM components, as well as the dynamic physical conditions of TME, which affect the behavior and aggressiveness of both drug-sensitive and drug-resistant LoVo cells differently.

3D Cell Culture Systems: Tumor Application, Advantages, and Disadvantages

The traditional two-dimensional (2D) in vitro cell culture system (on a flat support) has long been used in cancer research. However, this system cannot be fully translated into clinical trials to ideally represent physiological conditions. This culture cannot mimic the natural tumor microenvironment due to the lack of cellular communication (cell-cell) and interaction (cell-cell and cell-matrix). To overcome these limitations, three-dimensional (3D) culture systems are increasingly developed in research and have become essential for tumor research, tissue engineering, and basic biology research. 3D culture has received much attention in the field of biomedicine due to its ability to mimic tissue structure and function. The 3D matrix presents a highly dynamic framework where its components are deposited, degraded, or modified to delineate functions and provide a platform where cells attach to perform their specific functions, including adhesion, proliferation, communication, and apoptosis. So far, various types of models belong to this culture: either the culture based on natural or synthetic adherent matrices used to design 3D scaffolds as biomaterials to form a 3D matrix or based on non-adherent and/or matrix-free matrices to form the spheroids. In this review, we first summarize a comparison between 2D and 3D cultures. Then, we focus on the different components of the natural extracellular matrix that can be used as supports in 3D culture. Then we detail different types of natural supports such as matrigel, hydrogels, hard supports, and different synthetic strategies of 3D matrices such as lyophilization, electrospiding, stereolithography, microfluid by citing the advantages and disadvantages of each of them. Finally, we summarize the different methods of generating normal and tumor spheroids, citing their respective advantages and disadvantages in order to obtain an ideal 3D model (matrix) that retains the following characteristics: better biocompatibility, good mechanical properties corresponding to the tumor tissue, degradability, controllable microstructure and chemical components like the tumor tissue, favorable nutrient exchange and easy separation of the cells from the matrix.

Molecular study of the proliferation process of beta cells derived from pluripotent stem cells

BACKGROUND

Diabetes mellitus (DM) is a chronic metabolic disorder, increasing in the number of patients and poses a severe threat to human health. Significant advances have been made in DM treatment; the most important of which is differentiation and proliferation of beta cells from IPSCs.

METHODS

Data were collected from PUBMED at various time points up to the academic year of 2020. The related keywords are listed as follows: "Induced pluripotent stem cell", "Proliferation", "Growth factor", "Small molecule", "cardiotoxicity" and "Scaffold."

RESULT

The use of growth factors along with small molecules can be a good strategy for beta-cell proliferation. Also, proliferation of beta cells on nanofibers scaffolds can create a similar in vivo environment, that leads to increased function of beta-cell. Some transcription factors that cause beta cells proliferation play an important role in inflammation; so, it is essential to monitor them to prevent inflammation.

CONCLUSION

Finally, the simultaneous use of growth factors, micronutrients and scaffolds can be an excellent strategy to increase the proliferation and function of beta cells derived from IPSCs.

Biomarkers and cell-based models to predict the outcome of neoadjuvant therapy for rectal cancer patients

Rectal cancer constitutes approximately one-third of all colorectal cancers and contributes to considerable mortality globally. In contrast to colon cancer, the standard treatment for localized rectal cancer often involves neoadjuvant chemoradiotherapy. Tumour response rates to treatment show substantial inter-patient heterogeneity, indicating a need for treatment stratification. Consequently researchers have attempted to establish new means for predicting tumour response in order to assist in treatment decisions. In this review we have summarized published findings regarding potential biomarkers to predict neoadjuvant treatment response for rectal cancer tumours. In addition, we describe cell-based models that can be utilized both for treatment prediction and for studying the complex mechanisms involved.

Neutrally charged self-assembling peptide hydrogel recapitulates in vitro mechanisms of breast cancer progression

Self-assembling peptide hydrogels (SAPH) are a popular biomaterial due to their biocompatibility with a wide range of cell types, synthetic design, structural properties that provide a more accurate 3D microenvironment, and potential for cell- and/or drug-delivery system. Mimicking solid tumors in vitro using hydrogels is one method of testing anti-cancer drug efficacy and observing cancerous cell-ECM interactions within a 3D system. In this study, a SAPH, PeptiGel®Alpha1, was used to model in vitro the 3D breast tumor microenvironment. PeptiGel®Alpha1 is composed of entangled nanofibers with consistent diameter and mechanical properties similar to breast cancer that more accurately mimic the stiffness of breast tumor tissue than Matrigel® or collagen type I. PeptiGel®Alpha1 supported the viability and growth of the breast cancer cell lines MCF-7 and MDA-MB-231 and recapitulated key features of solid tumors such as hypoxia and invasion. MCF-7 cells in the hydrogels formed large spheroids resembling acini, while MDA-MB-231 remained dispersed. When treated with tamoxifen, PeptiGel®Alpha1 acted as a barrier, providing drug penetration geometry similar to that in vivo, providing better prediction of the drug effect. Finally, it was observed that MCF-7 cells engulfed the peptide matrix after 14 days, highlighting a potential use in drug delivery. PeptiGel®Alpha1 is a suitable platform for in vitro modeling of breast cancer.

In depth investigation of collagen non-enzymatic glycation by Raman spectroscopy

Non-enzymatic glycation is a post-translational modification of long-lived matrix proteins such as type I collagen. It occurs during aging and leads to the formation of advanced glycation end-products (AGEs). AGE accumulation is associated with severe complications in chronic and age-related diseases. The assessment of modifications induced by this (patho)physiological process represents an interest in biology and medicine for a better patient care. The objective of our work was to position the interest of Raman spectroscopy in the quantification of collagen glycation. Two types of in vitro glycation were used by incubating collagen samples, at different durations, with ribose or glyoxylic acid; these reducing agents acting on the chemical specificity of the glycation reaction. Glycation efficiency was evaluated by the liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) quantification of carboxymethyllysine (CML) and pentosidine, which are among the most studied AGEs. Raman data were processed by PCA coupled to validity indices and Lasso regression as multivariate analysis tools. Regression models were constructed by considering the LC-MS/MS results as reference values. A marked variability was observed within the Raman datasets making difficult the identification of spectral differences between control and ribose-treated collagen samples. By taking advantage of the chemical specificity of the glyoxylic acid treatment leading to CML formation, on one hand, and the feature selection included in the Lasso algorithm, on the other hand, Raman markers associated with glycation were identified. The assigned vibrations corresponded to modifications of side chains of collagen. In addition, a threshold of CML concentration was determined as quantitative indicator of the applicability of Raman spectroscopy for potential patient follow-up purposes. Although lacking in sensitivity to directly detect AGEs in collagen, Raman spectroscopy allows to highlight the molecular modifications of collagen induced by glycation.

Development and validation of an in-silico tool for the study of therapeutic agents in 3D cell cultures

Computational models constitute a fundamental asset for cancer research and drug R&D, as they provide controlled environments for testing of hypotheses and are characterized by the total knowledge of the system. These features are particularly useful for 3D cell culture models where a complex interaction among cells and their environments ensues. In this work, we present a programmable simulator capable of reproducing the behavior of cells cultured in 3D scaffolds and their response to pharmacological treatment. This system will be shown to be able to accurately describe the temporal evolution of the density of a population of MDA-MB-231 cells following their treatment with different concentrations of doxorubicin, together with a newly described drug-resistance mechanism and potential re-sensitization strategy. An extensive technical description of this model will be coupled to its experimental validation and to an analysis aimed at identifying which variables and behaviors account for differences in the response to treatment. Comprehensively, this work contributes to the growing field of integrated in-silico/in-vitro analysis of biological processes which has great potential for both the increase of our scientific knowledge and the development of novel, more effective treatments.

Best of Both Hydrogel Worlds: Harnessing Bioactivity and Tunability by Incorporating Glycosaminoglycans in Collagen Hydrogels

Collagen, the most abundant protein in mammals, has garnered the interest of scientists for over 50 years. Its ubiquitous presence in all body tissues combined with its excellent biocompatibility has led scientists to study its potential as a biomaterial for a wide variety of biomedical applications with a high degree of success and widespread clinical approval. More recently, in order to increase their tunability and applicability, collagen hydrogels have frequently been co-polymerized with other natural and synthetic polymers. Of special significance is the use of bioactive glycosaminoglycans-the carbohydrate-rich polymers of the ECM responsible for regulating tissue homeostasis and cell signaling. This review covers the recent advances in the development of collagen-based hydrogels and collagen-glycosaminoglycan blend hydrogels for biomedical research. We discuss the formulations and shortcomings of using collagen in isolation, and the advantages of incorporating glycosaminoglycans (GAGs) in the hydrogels. We further elaborate on modifications used on these biopolymers for tunability and discuss tissue specific applications. The information presented herein will demonstrate the versatility and highly translational value of using collagen blended with GAGs as hydrogels for biomedical engineering applications.

Preclinical Evaluation of the Oncolytic Vaccinia Virus TG6002 by Translational Research on Canine Breast Cancer

Oncolytic virotherapy is a promising therapeutic approach for the treatment of cancer. TG6002 is a recombinant oncolytic vaccinia virus deleted in the thymidine kinase and ribonucleotide reductase genes and armed with the suicide gene FCU1, which encodes a bifunctional chimeric protein that efficiently catalyzes the direct conversion of the nontoxic 5-fluorocytosine into the toxic metabolite 5-fluorouracil. In translational research, canine tumors and especially mammary cancers are relevant surrogates for human cancers and can be used as preclinical models. Here, we report that TG6002 is able to replicate in canine tumor cell lines and is oncolytic in such cells cultured in 2D or 3D as well as canine mammary tumor explants. Furthermore, intratumoral injections of TG6002 lead to inhibition of the proliferation of canine tumor cells grafted into mice. 5-fluorocytosine treatment of mice significantly improves the anti-tumoral activity of TG6002 infection, a finding that can be correlated with its conversion into 5-fluorouracil within infected fresh canine tumor biopsies. In conclusion, our study suggests that TG6002 associated with 5-fluorocytosine is a promising therapy for human and canine cancers.

Porous Polymeric Microspheres With Controllable Pore Diameters for Tissue Engineered Lung Tumor Model Development

Complex cell cultures are more representative of in vivo conditions than conventionally used monolayer cultures, and are hence being investigated for predictive screening of therapeutic agents. Poly lactide co-glycolide (PLGA) polymer is frequently used in the development of porous substrates for complex cell culture. Substrates or scaffolds with highly interconnected, micrometric pores have been shown to positively impact tissue model formation by enhancing cell attachment and infiltration. We report a novel alginate microsphere (AMS)-based controlled pore formation method for the development of porous, biodegradable PLGA microspheres (PPMS), for tissue engineered lung tumor model development. The AMS porogen, non-porous PLGA microspheres (PLGAMS) and PPMS had spherical morphology (mean diameters: 10.3 ± 4, 79 ± 21.8, and 103 ± 30 μm, respectively). The PPMS had relatively uniform pores and a porosity of 45.5%. Degradation studies show that PPMS effectively maintained their structural integrity with time whereas PLGAMS showed shrunken morphology. The optimized cell seeding density on PPMS was 25 × 103 cells/mg of particles/well. Collagen coating on PPMS significantly enhanced the attachment and proliferation of co-cultures of A549 lung adenocarcinoma and MRC-5 lung fibroblast cells. Preliminary proof-of-concept drug screening studies using mono- and combination anti-cancer therapies demonstrated that the tissue-engineered lung tumor model had a significantly higher resistance to the tested drugs than the monolayer co-cultures. These studies indicate that the PPMS with controllable pore diameters may be a suitable platform for the development of complex tumor cultures for early in vitro drug screening applications.

Towards normalization selection of Raman data in the context of protein glycation: application of validity indices to PCA processed spectra

Vibrational data of biological samples require appropriate pre-processing for ensuring relevant interpretation. Here, mathematical criteria (validity indices) are used to select how to normalize Raman data collected in the protein glycation context.

Unravelling Receptor and RGD Motif Dependence of Retargeted Adenoviral Vectors using Advanced Tumor Model Systems

Recent advances in engineering adenoviruses are paving the way for new therapeutic gene delivery approaches in cancer. However, there is limited knowledge regarding the impact of adenoviral retargeting on transduction efficiency in more complex tumor architectures, and the role of the RGD loop at the penton base in retargeting is unclear. To address this gap, we used tumor models of increasing complexity to study the role of the receptor and the RGD motif. Employing tumor-fibroblast co-culture models, we demonstrate the importance of the RGD motif for efficient transduction in 2D through the epithelial cell adhesion molecule (EpCAM), but not the epidermal growth factor receptor (EGFR). Via optical clearing of co-culture spheroids, we show that the RGD motif is required for transduction via both receptors in 3D tumor architectures. We subsequently employed a custom-designed microfluidic model containing collagen-embedded tumor spheroids, mimicking the interplay between interstitial flow, extracellular matrix and adenoviral transduction. Image analysis of on-chip cleared spheroids indicated the importance of the RGD motif for on-chip adenoviral transduction. Together, our results show the interrelationship between receptor characteristics, the RGD motif, the 3D tumor architecture and retargeted adenoviral transduction efficiency. The findings are important for the rational design of next-generation therapeutic adenoviruses.

Pyridine-Containing Macrocycles Display MMP-2/9 Inhibitory Activity and Distinct Effects on Migration and Invasion of 2D and 3D Breast Cancer Models

The role of metalloproteinases (MMPs) on the migration and invasion of cancer cells has been correlated with tumor aggressiveness, namely with the up-regulation of MMP-2 and 9. Herein, two pyridine-containing macrocyclic compounds, [15]pyN₅ and [16]pyN₅, were synthesized, chemically characterized and evaluated as potential MMP inhibitors for breast cancer therapy using 3D and 2D cellular models. [15]pyN₅ and [16]pyN₅ (5–20 µM) showed a marked inhibition of MMPs activity (100% at concentrations ≥ 7.5 μM) when compared to ARP-100, a known MMP inhibitor. The inhibitory activity of [15]pyN₅ and [16]pyN₅ was further supported through in silico docking studies using Goldscore and ChemPLP scoring functions. Moreover, although no significant differences were observed in the invasion studies in the presence of all MMPs inhibitors, cell migration was significantly inhibited by both pyridine-containing macrocycles at concentrations above 5 μM in 2D cells (p < 0.05). In spheroids, the same effect was observed, but only with [16]pyN₅ at 20 μM and ARP-100 at 40 μM. Overall, [15]pyN₅ and [16]pyN₅ led to impaired breast cancer cell migration and revealed to be potential inhibitors of MMPs 2 and 9.

Safe and Effective Delivery of Antitumor Drug Using Mesenchymal Stem Cells Impregnated with Submicron Carriers

An important area in modern malignant tumor therapy is the optimization of antitumor drugs pharmacokinetics. The use of some antitumor drugs is limited in clinical practice due to their high toxicity. Therefore, the strategy for optimizing the drug pharmacokinetics focuses on the generation of high local concentrations of these drugs in the tumor area with minimal systemic and tissue-specific toxicity. This can be achieved by encapsulation of highly toxic antitumor drug (vincristine (VCR) that is 20-50 times more toxic than widely used the antitumor drug doxorubicin) into nano- and microcarriers with their further association into therapeutically relevant cells that possess the ability to migrate to sites of tumor. Here, we fundamentally examine the effect of drug carrier size on the behavior of human mesenchymal stem cells (hMSCs), including internalization efficiency, cytotoxicity, cell movement, to optimize the conditions for the development of carrier-hMSCs drug delivery platform. Using the malignant tumors derived from patients, we evaluated the capability of hMSCs associated with VCR-loaded carriers to target tumors using a three-dimensional spheroid model in collagen gel. Compared to free VCR, the developed hMSC-based drug delivery platform showed enhanced antitumor activity regarding those tumors that express CXCL12 (stromal cell-derived factor-1 (SDF-1)) gene, inducing directed migration of hMSCs via CXCL12 (SDF-1)/CXCR4 pathway. These results show that the combination of encapsulated antitumor drugs and hMSCs, which possess the properties of active migration into tumors, is therapeutically beneficial and demonstrated high efficiency and low systematic toxicity, revealing novel strategies for chemotherapy in the future.

Type I collagen aging impairs discoidin domain receptor 2-mediated tumor cell growth suppression

Tumor cells are confronted to a type I collagen rich environment which regulates cell proliferation and invasion. Biological aging has been associated with structural changes of type I collagen. Here, we address the effect of collagen aging on cell proliferation in a three-dimensional context (3D).

We provide evidence for an inhibitory effect of adult collagen, but not of the old one, on proliferation of human fibrosarcoma HT-1080 cells. This effect involves both the activation of the tyrosine kinase Discoidin Domain Receptor 2 (DDR2) and the tyrosine phosphatase SHP-2. DDR2 and SHP-2 were less activated in old collagen. DDR2 inhibition decreased SHP-2 phosphorylation in adult collagen and increased cell proliferation to a level similar to that observed in old collagen.

In the presence of old collagen, a high level of JAK2 and ERK1/2 phosphorylation was observed while expression of the cell cycle negative regulator p21^CIP1 was decreased. Inhibition of DDR2 kinase function also led to an increase in ERK1/2 phosphorylation and a decrease in p21^CIP1 expression. Similar signaling profile was observed when DDR2 was inhibited in adult collagen. Altogether, these data suggest that biological collagen aging could increase tumor cell proliferation by reducingthe activation of the key matrix sensor DDR2.

Biomimetic tumor microenvironments based on collagen matrices

This review provides an overview of the current approaches to engineer defined 3D matrices for the investigation of tumor cell behaviorin vitro, with a focus on collagen-based fibrillar systems.

Doxorubicin Drug-Eluting Embolic Chemoembolization of Hepatocellular Carcinoma: Study of Midterm Doxorubicin Delivery in Resected Liver Specimens

This study evaluated the midterm delivery of doxorubicin in liver specimens from patients (N = 4) with hepatocellular carcinoma treated with drug-eluting embolic (DEE) transarterial chemoembolization. The patients had surgical resection 57, 79, 80 and 105 days after doxorubicin DEE chemoembolization. Doxorubicin concentrations inside embolic particles and in surrounding tissues were assessed by infrared microspectroscopy and microspectrofluorimetry, respectively. Embolic particles still contained doxorubicin and provided sustained drug delivery within targeted tissues 80 days after chemoembolization. Doxorubicin was undetectable after 105 days. In addition, aggregation of embolic particles inside vessel lumina was associated with slower doxorubicin elution and higher tissue concentrations when the number of aggregated embolic particles increased.

Enhanced migration of murine fibroblast-like 3T3-L1 preadipocytes on type I collagen-coated dish is reversed by silibinin treatment

Migration of fibroblast-like preadipocytes is important for the development of adipose tissue, whereas excessive migration is often responsible for impaired adipose tissue related with obesity and fibrotic diseases. Type I collagen (collagen I) is the most abundant component of extracellular matrix and has been shown to regulate fibroblast migration in vitro, but its role in adipose tissue is not known. Silibinin is a bioactive natural flavonoid with antioxidant and antimetastasis activities. In this study, we found that type I collagen coating promoted the proliferation and migration of murine 3T3-L1 preadipocytes in a dose-dependent manner, implying that collagen I could be an extracellular signal. Regarding the mechanisms of collagen I-stimulated 3T3-L1 migration, we found that NF-κB p65 is activated, including the increased nuclear translocation of NF-κB p65 as well as the upregulation of NF-κB p65 phosphorylation and acetylation, accompanied by the increased expressions of proinflammatory factors and the generation of reactive oxygen species (ROS). Reduction of collagen I-enhanced migration of cells by treatment with silibinin was associated with suppression of NF-κB p65 activity and ROS generation, and negatively correlated with the increasing sirt1 expression. Taken together, the enhanced migration of 3T3-L1 cells induced on collagen I-coated dish is mediated by the activation of NF-κB p65 function and ROS generation that can be alleviated with silibinin by upregulation of sirt1, leading to the repression of NF-κB p65 function and ROS generation.

Mitosis-Mediated Intravasation in a Tissue-Engineered Tumor-Microvessel Platform

Intravasation involves the migration of tumor cells across the local endothelium and escape into vessel flow. Although tumor cell invasiveness has been correlated to increased intravasation, the details of transendothelial migration and detachment into circulation are still unclear. Here, we analyzed the intravasation of invasive human breast cancer cells within a tissue-engineered microvessel model of the tumor microenvironment. Using live-cell fluorescence microscopy, we captured 2,330 hours of tumor cell interactions with functional microvessels and provide evidence for a mitosis-mediated mechanism where tumor cells located along the vessel periphery are able to disrupt the vessel endothelium through cell division and detach into circulation. This model provides a framework for understanding the physical and biological parameters of the tumor microenvironment that mediate intravasation of tumor cells across an intact endothelium. Cancer Res; 77(22); 6453-61. ©2017 AACR.

Applications of label-free, quantitative phase holographic imaging cytometry to the development of multi-specific nanoscale pharmaceutical formulations

A label-free, high content, time-lapse holographic imaging system was applied to studies in pharmaceutical compound development. Multiple fields of cellular images are obtained over typically several day evaluations within standard CO2 incubators. Events are segmented to obtain population data of cellular features, which are displayed in scattergrams and histograms. Cell tracking is accomplished, accompanied by Cartesian plots of cell movement, as well as plots of cell features vs. time in novel 4-D displays of X position, Y position, time, and cell thickness. Our review of the instrument validation data includes 1) tracking of Giant HeLa cells, which may be undergoing neosis, a process of tumor stem cell generation; 2) tracking the effects of cell cycle related toxic agents on cell lines; 3) using MicroRNAs to reverse the polarization state in macrophages to induce tumor cell killing; 4) development of liposomal nanoformulations to overcome Multi-Drug Resistance (MDR) in ovarian cancer cells; and 5) development of dual sensitive micelles to specifically target matrix metalloproteinase 2 (MMP2) over-expressing cell lines. © 2017 International Society for Advancement of Cytometry.

Contributions of 3D Cell Cultures for Cancer Research

Cancer cell lines have contributed immensely in understanding the complex physiology of cancers. They are excellent material for studies as they offer homogenous samples without individual variations and can be utilised with ease and flexibility. Also, the number of assays and end-points one can study is almost limitless; with the advantage of improvising, modifying or altering several variables and methods. Literally, a new dimension to cancer research has been achieved by the advent of 3Dimensional (3D) cell culture techniques. This approach increased many folds the ways in which cancer cell lines can be utilised for understanding complex cancer biology. 3D cell culture techniques are now the preferred way of using cancer cell lines to bridge the gap between the 'absolute in vitro' and 'true in vivo'. The aspects of cancer biology that 3D cell culture systems have contributed include morphology, microenvironment, gene and protein expression, invasion/migration/metastasis, angiogenesis, tumour metabolism and drug discovery, testing chemotherapeutic agents, adaptive responses and cancer stem cells. We present here, a comprehensive review on the applications of 3D cell culture systems for these aspects of cancers. J. Cell. Physiol. 232: 2679-2697, 2017. © 2016 Wiley Periodicals, Inc.

Highlighting the impact of aging on type I collagen: label-free investigation using confocal reflectance microscopy and diffuse reflectance spectroscopy in 3D matrix model

During aging, alterations of extracellular matrix proteins contribute to various pathological phenotypes. Among these alterations, type I collagen cross-linking and associated glycation products accumulation over time detrimentally affects its physico-chemical properties, leading to alterations of tissue biomechanical stability. Here, different-age collagen 3D matrices using non-destructive and label-free biophotonic techniques were analysed to highlight the impact of collagen I aging on 3D constructs, at macroscopic and microscopic levels. Matrices were prepared with collagens extracted from tail tendons of rats (newborns, young and old adults) to be within the physiological aging process. The data of diffuse reflectance spectroscopy reveal that aging leads to an inhibition of fibril assembly and a resulting decrease of gel density. Investigations by confocal reflectance microscopy highlight poor-fibrillar structures in oldest collagen networks most likely related to the glycation products accumulation. Complementarily, an infrared analysis brings out marked spectral variations in the Amide I profile, specific of the peptidic bond conformation and for carbohydrates vibrations as function of collagen-age. Interestingly, we also highlight an unexpected behavior for newborn collagen, exhibiting poorly-organized networks and microscopic features close to the oldest collagen. These results demonstrate that changes in collagen optical properties are relevant for investigating the incidence of aging in 3D matrix models.

Three-Dimensional Assay for Studying Breast Cancer Cell Invasion

Cancer cell invasion is a complex process that naturally occurs in a three-dimensional (3-D) environment comprised of tumor cells and extracellular matrix components (ECM). Therefore, examining the invasive ability of breast cancer cells in a 3-D assay is imperative to discovering novel treatment strategies aimed at preventing cancer invasion and metastasis. Here, I describe a method to quantitatively measure the number of invaded cancer cells within a 3-D microenvironment and determine the effects of potential drugs on this cellular process.

Mixed Nanosized Polymeric Micelles as Promoter of Doxorubicin and miRNA-34a Co-Delivery Triggered by Dual Stimuli in Tumor Tissue

Dual stimuli-sensitive mixed polymeric micelles (MM) are developed for co-delivery of the endogenous tumor suppressor miRNA-34a and the chemotherapeutic agent doxorubicin (Dox) into cancer cells. The novelty of the system resides in two stimuli-sensitive prodrugs, a matrix metalloproteinase 2 (MMP2)-sensitive Dox conjugate and a reducing agent (glutathione, GSH)-sensitive miRNA-34a conjugate, self-assembled in a single particle decorated with a polyethylene glycol corona for longevity, and a cell-penetrating peptide (TATp) for enhanced intracellular delivery. The MMP2-sensitivity of the system results in threefold higher cytotoxicity in MMP2-overexpressing HT1080 cells compared to low MMP2-expressing MCF7 cells. Cellular internalization of Dox increases by more than 70% after inclusion of TATp to the formulation. MMP2-sensitive MM also inhibits proliferation and migration of HT1080 cells. Moreover, GSH-sensitive MM allows for an efficient downregulation of Bcl2, survivin, and notch1 (65%, 55%, and 46%, respectively) in HT1080 cells. Combination of both conjugates in dual sensitive MM reduces HT1080 cell viability to 40% and expression of Bcl2 and survivin. Finally, 50% cell death is observed in 3D models of tumor mass. The results confirm the potential of the MM to codeliver miRNA-34a and doxorubicin triggered by dual stimuli inherent of tumor tissues.

Role of LRP-1 in cancer cell migration in 3-dimensional collagen matrix

The low-density lipoprotein receptor-related protein-1 (LRP-1) is a member of Low Density Lipoprotein Receptor (LDLR) family, which is ubiquitously expressed and which is described as a multifunctional endocytic receptor which mediates the clearance of various extracellular matrix molecules including serine proteinases, proteinase-inhibitor complexes, and matricellular proteins. Several studies showed that high LRP-1 expression promotes breast cancer cell invasiveness, and LRP-1 invalidation leads to cell motility abrogation in both tumor and non-tumor cells. Furthermore, our group has reported that LRP-1 silencing prevents the invasion of a follicular thyroid carcinoma despite increased pericellular proteolytic activities from MMP2 and uPA using a 2D-cell culture model. As the use of 3D culture systems is becoming more and more popular due to their promise as enhanced models of tissue physiology, the aim of the present work is to characterize for the first time how the 3D collagen type I matrix may impact the ability of LRP-1 to regulate the migratory properties of thyroid carcinoma using as a model FTC-133 cells. Our results show that inhibition of LRP-1 activity or expression leads to morphological changes affecting cell-matrix interactions, reorganizations of the actin-cytoskeleton especially by inhibiting FAK activation and increasing RhoA activity and MLC-2 phosphorylation, thus preventing cell migration. Taken together, our results suggest that LRP-1 silencing leads to a decrease of cell migratory capacity in a 3D configuration.

3D culture of Her2+ breast cancer cells promotes AKT to MAPK switching and a loss of therapeutic response

BACKGROUND

The Her2 receptor is overexpressed in up to 25 % of breast cancers and is associated with a poor prognosis. Around half of Her2+ breast cancers also express the estrogen receptor and treatment for such tumours can involve both endocrine and Her2-targeted therapies. However, despite preclinical data supporting the effectiveness of these agents, responses can vary widely in the clinical setting. In light of the increasing evidence pointing to the interplay between the tumour and its extracellular microenvironment as a significant determinant of therapeutic sensitivity and response here we investigated the impact of 3D matrix culture of breast cancer cells on their therapeutic sensitivity.

METHODS

A 3D Matrigel-based culture system was established and optimized for the growth of ER+/Her2+ breast cancer cell models. Growth of cells in response to trastuzumab and endocrine agents in 3D culture versus routine monolayer culture were assessed using cell counting and Ki67 staining. Endogenous and trastuzumab-modulated signalling pathway activity in 2D and 3D cultures were assessed using Western blotting.

RESULTS

Breast cancer cells in 3D culture displayed an attenuated response to both endocrine agents and trastuzumab compared with cells cultured in traditional 2D monolayers. Underlying this phenomenon was an apparent matrix-induced shift from AKT to MAPK signalling; consequently, suppression of MAPK in 3D cultures restores therapeutic response.

CONCLUSION

These data suggest that breast cancer cells in 3D culture display a reduced sensitivity to therapeutic agents which may be mediated by internal MAPK-mediated signalling. Targeting of adaptive pathways that maintain growth in 3D culture may represent an effective strategy to improve therapeutic response clinically.

Non-Muscle Myosin II Isoforms Have Different Functions in Matrix Rearrangement by MDA-MB-231 Cells

The role of a stiffening extra-cellular matrix (ECM) in cancer progression is documented but poorly understood. Here we use a conditioning protocol to test the role of nonmuscle myosin II isoforms in cell mediated ECM arrangement using collagen constructs seeded with breast cancer cells expressing shRNA targeted to either the IIA or IIB heavy chain isoform. While there are several methods available to measure changes in the biophysical characteristics of the ECM, we wanted to use a method which allows for the measurement of global stiffness changes as well as a dynamic response from the sample over time. The conditioning protocol used allows the direct measurement of ECM stiffness. Using various treatments, it is possible to determine the contribution of various construct and cellular components to the overall construct stiffness. Using this assay, we show that both the IIA and IIB isoforms are necessary for efficient matrix remodeling by MDA-MB-231 breast cancer cells, as loss of either isoform changes the stiffness of the collagen constructs as measured using our conditioning protocol. Constructs containing only collagen had an elastic modulus of 0.40 Pascals (Pa), parental MDA-MB-231 constructs had an elastic modulus of 9.22 Pa, while IIA and IIB KD constructs had moduli of 3.42 and 7.20 Pa, respectively. We also calculated the cell and matrix contributions to the overall sample elastic modulus. Loss of either myosin isoform resulted in decreased cell stiffness, as well as a decrease in the stiffness of the cell-altered collagen matrices. While the total construct modulus for the IIB KD cells was lower than that of the parental cells, the IIB KD cell-altered matrices actually had a higher elastic modulus than the parental cell-altered matrices (4.73 versus 4.38 Pa). These results indicate that the IIA and IIB heavy chains play distinct and non-redundant roles in matrix remodeling.

A membrane-type-1 matrix metalloproteinase (MT1-MMP)-discoidin domain receptor 1 axis regulates collagen-induced apoptosis in breast cancer cells

During tumour dissemination, invading breast carcinoma cells become confronted with a reactive stroma, a type I collagen-rich environment endowed with anti-proliferative and pro-apoptotic properties. To develop metastatic capabilities, tumour cells must acquire the capacity to cope with this novel microenvironment. How cells interact with and respond to their microenvironment during cancer dissemination remains poorly understood. To address the impact of type I collagen on the fate of tumour cells, human breast carcinoma MCF-7 cells were cultured within three-dimensional type I collagen gels (3D COL1). Using this experimental model, we have previously demonstrated that membrane type-1 matrix metalloproteinase (MT1-MMP), a proteinase overexpressed in many aggressive tumours, promotes tumour progression by circumventing the collagen-induced up-regulation of BIK, a pro-apoptotic tumour suppressor, and hence apoptosis. Here we performed a transcriptomic analysis to decipher the molecular mechanisms regulating 3D COL1-induced apoptosis in human breast cancer cells. Control and MT1-MMP expressing MCF-7 cells were cultured on two-dimensional plastic plates or within 3D COL1 and a global transcriptional time-course analysis was performed. Shifting the cells from plastic plates to 3D COL1 activated a complex reprogramming of genes implicated in various biological processes. Bioinformatic analysis revealed a 3D COL1-mediated alteration of key cellular functions including apoptosis, cell proliferation, RNA processing and cytoskeleton remodelling. By using a panel of pharmacological inhibitors, we identified discoidin domain receptor 1 (DDR1), a receptor tyrosine kinase specifically activated by collagen, as the initiator of 3D COL1-induced apoptosis. Our data support the concept that MT1-MMP contributes to the inactivation of the DDR1-BIK signalling axis through the cleavage of collagen fibres and/or the alteration of DDR1 receptor signalling unit, without triggering a drastic remodelling of the transcriptome of MCF-7 cells.

3D cell culture systems: advantages and applications

Cell cultures are important material of study for the variety of advantages that they offer. Both established continuous cell lines and primary cell cultures continue to be invaluable for basic research and for direct applications. Technological advancements are necessary to address emerging complex challenges and the way cells are cultured in vitro is an area of intense activity. One important advancement in cell culture techniques has been the introduction of three dimensional culture systems. This area is one of the fastest growing experimental approaches in life sciences. Augmented with advancements in cell imaging and analytical systems, as well as the applications of new scaffolds and matrices, cells have been increasingly grown as three dimensional models. Such cultures have proven to be closer to in vivo natural systems, thus proving to be useful material for many applications. Here, we review the three dimensional way of culturing cells, their advantages, the scaffolds and matrices currently available, and the applications of such cultures in major areas of life sciences.

Microscale 3D collagen cell culture assays in conventional flat-bottom 384-well plates

Three-dimensional (3D) culture systems such as cell-laden hydrogels are superior to standard two-dimensional (2D) monolayer cultures for many drug-screening applications. However, their adoption into high-throughput screening (HTS) has been lagging, in part because of the difficulty of incorporating these culture formats into existing robotic liquid handling and imaging infrastructures. Dispensing cell-laden prepolymer solutions into 2D well plates is a potential solution but typically requires large volumes of reagents to avoid evaporation during polymerization, which (1) increases costs, (2) makes drug penetration variable and (3) complicates imaging. Here we describe a technique to efficiently produce 3D microgels using automated liquid-handling systems and standard, nonpatterned, flat-bottomed, 384-well plates. Sub-millimeter-diameter, cell-laden collagen gels are deposited on the bottom of a ~2.5 mm diameter microwell with no concerns about evaporation or meniscus effects at the edges of wells, using aqueous two-phase system patterning. The microscale cell-laden collagen-gel constructs are readily imaged and readily penetrated by drugs. The cytotoxicity of chemotherapeutics was monitored by bioluminescence and demonstrated that 3D cultures confer chemoresistance as compared with similar 2D cultures. Hence, these data demonstrate the importance of culturing cells in 3D to obtain realistic cellular responses. Overall, this system provides a simple and inexpensive method for integrating 3D culture capability into existing HTS infrastructure.

Carboxymethylcellulose hydrogels support central nervous system-derived tumor-cell chemotactic migration: Comparison with conventional extracellular matrix macromolecules

The local microenvironment plays an important role in maintaining the dynamics of the extracellular matrix and the cell–extracellular matrix relationship. The extracellular matrix is a complex network of macromolecules with distinct mechanical and biochemical characteristics. Disruptions in extracellular matrix homeostasis are associated with the onset of cancer. The extracellular matrix becomes highly disorganized, and the cell–matrix relationship changes, resulting in altered cell-signaling processes and metastasis. Medulloblastoma is one of the most common malignant pediatric brain tumors in the United States. In order to gain a better understanding of the interplay between cell–extracellular matrix interactions and cell-migratory responses in tumors, eight different matrix macromolecule formulations were investigated using a medulloblastoma-derived cell line: poly-d-lysine, matrigel, laminin, collagen 1, fibronectin, a 10% blend of laminin–collagen 1, a 20% blend of laminin–collagen 1, and a cellulose-derived hydrogel, carboxymethylcellulose. Over time, the average changes in cell morphology were quantified in 2D and 3D, as was migration in the presence and absence of the chemoattractant, epidermal growth factor. Data revealed that carboxymethylcellulose allowed for a cell–extracellular matrix relationship typically believed to be present in tumors, with cells exhibiting a rounded, amoeboid morphology consistent with chemotactic migration, while the other matrices promoted an elongated cell shape as well as both haptotactic and chemotactic motile processes. Therefore, carboxymethylcellulose hydrogels may serve as effective platforms for investigating central nervous system-derived tumor-cell migration in response to soluble factors.

The multiple facets of drug resistance: one history, different approaches

Some cancers like melanoma and pancreatic and ovarian cancers, for example, commonly display resistance to chemotherapy, and this is the major obstacle to a better prognosis of patients. Frequently, literature presents studies in monolayer cell cultures, 3D cell cultures or in vivo studies, but rarely the same work compares results of drug resistance in different models. Several of these works are presented in this review and show that usually cells in 3D culture are more resistant to drugs than monolayer cultured cells due to different mechanisms. Searching for new strategies to sensitize different tumors to chemotherapy, many methods have been studied to understand the mechanisms whereby cancer cells acquire drug resistance. These methods have been strongly advanced along the years and therapies using different drugs have been increasingly proposed to induce cell death in resistant cells of different cancers. Recently, cancer stem cells (CSCs) have been extensively studied because they would be the only cells capable of sustaining tumorigenesis. It is believed that the resistance of CSCs to currently used chemotherapeutics is a major contributing factor in cancer recurrence and later metastasis development. This review aims to appraise the experimental progress in the study of acquired drug resistance of cancer cells in different models as well as to understand the role of CSCs as the major contributing factor in cancer recurrence and metastasis development, describing how CSCs can be identified and isolated.

A strategy for integrating essential three-dimensional microphysiological systems of human organs for realistic anticancer drug screening

Cancer is one of the leading causes of morbidity and mortality around the world. Despite some success, traditional anticancer drugs developed to reduce tumor growth face important limitations primarily due to undesirable bone marrow and cardiovascular toxicity. Many drugs fail in clinical development after showing promise in preclinical trials, suggesting that the available in vitro and animal models are poor predictors of drug efficacy and toxicity in humans. Thus, novel models that more accurately mimic the biology of human organs are necessary for high-throughput drug screening. Three-dimensional (3D) microphysiological systems can utilize induced pluripotent stem cell technology, tissue engineering, and microfabrication techniques to develop tissue models of human tumors, cardiac muscle, and bone marrow on the order of 1 mm(3) in size. A functional network of human capillaries and microvessels to overcome diffusion limitations in nutrient delivery and waste removal can also nourish the 3D microphysiological tissues. Importantly, the 3D microphysiological tissues are grown on optically clear platforms that offer non-invasive and non-destructive image acquisition with subcellular resolution in real time. Such systems offer a new paradigm for high-throughput drug screening and will significantly improve the efficiency of identifying new drugs for cancer treatment that minimize cardiac and bone marrow toxicity.

Critical analysis of 3-D organoid in vitro cell culture models for high-throughput drug candidate toxicity assessments

Drug failure due to toxicity indicators remains among the primary reasons for staggering drug attrition rates during clinical studies and post-marketing surveillance. Broader validation and use of next-generation 3-D improved cell culture models are expected to improve predictive power and effectiveness of drug toxicological predictions. However, after decades of promising research significant gaps remain in our collective ability to extract quality human toxicity information from in vitro data using 3-D cell and tissue models. Issues, challenges and future directions for the field to improve drug assay predictive power and reliability of 3-D models are reviewed.

Pro-metastatic tumor–stroma interactions in breast cancer

The vast majority of breast cancer-related deaths are due to metastatic disease. Reciprocal and complex interactions between epithelial tumor cells and the various components of the tumor microenvironment influence tumor progression and metastases although the molecular mechanisms underlying these metastasis-promoting effects are not fully characterized. Identifying and understanding pathways of tumor–stroma cross-talk are likely to lead to the development of novel prognostic biomarkers for metastasis and strategies to prevent metastasis at its earliest stages, resulting in improved patient outcomes.

Influence of a three-dimensional, microarray environment on human cell culture in drug screening systems

We have used a modified 3D cellular microarray platform for the high-throughput analysis of growth, cytotoxicity, and protein expression profile of a human hepatocellular carcinoma cell line, HepG2, in alginate. The results obtained were compared to analogous studies in 2D and 3D environments at the microtiter scale. The antiproliferative effects of four drugs, tamoxifen, 5-fluorouracil, doxorubicin, and amitriptyline, were studied as a function of seeding density in the three different culture platforms. The chemosensitivity of HepG2 cells to all four compounds decreased substantially with increasing cell number in the 2D and 3D microtiter-based cultures, while no seeding density dependence was observed in the IC(50) values obtained in the 3D microarray culture platform. These results can be rationalized based on the development of confluence-dependent resistance in cultures where proliferation is restricted by cell-cell contacts and nutrient availability, as is the case for both of the microtiter-based cultures. Additionally, further development of an on-chip, in-cell immunofluorescence assay provided quantitative data on the levels of specific target proteins involved in proliferation, adhesion, angiogenesis and drug metabolism, and was used to compare expression profiles between 2D and 3D environments. The up-regulation of several CYP450 enzymes, β1-integrin and vascular endothelial growth factor (VEGF) in the 3D microarray cultures suggests that this platform provides a more in vivo-like environment allowing cells to approach their natural phenotype.

Extracellular matrix proteins modulate antimigratory and apoptotic effects of Doxorubicin

Anticancer drug resistance is a multifactorial process that includes acquired and de novo drug resistances. Acquired resistance develops during treatment, while de novo resistance is the primary way for tumor cells to escape chemotherapy. Tumor microenvironment has been recently shown to be one of the important factors contributing to de novo resistance and called environment-mediated drug resistance (EMDR). Two forms of EMDR have been described: soluble factor-mediated drug resistance (SFM-DR) and cell adhesion-mediated drug resistance (CAM-DR). Anthracyclines, among the most potent chemotherapeutic agents, are widely used in clinics against hematopoietic and solid tumors. Their main mechanism of action relies on the inhibition of topoisomerase I and/or II and the induction of apoptosis. Beyond this well-known antitumor activity, it has been recently demonstrated that anthracyclines may display potent anti-invasive effects when used at subtoxic concentrations. In this paper, we will describe two particular modes of EMDR by which microenvironment may influence tumor-cell response to one of these anthracyclines, doxorubicin. The first one considers the influence of type I collagen on the antimigratory effect of doxorubicin (CAM-DR). The second considers the protection of tumor cells by thrombospondin-I against doxorubicin-induced apoptosis (SFM-DR).

Lab-in-a-tube: ultracompact components for on-chip capture and detection of individual micro-/nanoorganisms

A review of present and future on-chip rolled-up devices, which can be used to develop lab-in-a-tube total analysis systems, is presented. Lab-in-a-tube is the integration of numerous rolled-up components into a single device constituting a microsystem of hundreds/thousands of independent units on a chip, each individually capable of sorting, detecting and analyzing singular organisms. Such a system allows for a scale-down of biosensing systems, while at the same time increasing the data collection through a large, smart array of individual biosensors. A close look at these ultracompact components which have been developed over the past decade is given. Methods for the capture of biomaterial are laid out and progress of cell culturing in three-dimensional scaffolding is detailed. Rolled-up optical sensors based on photoluminescence, optomechanics, optofluidics and metamaterials are presented. Magnetic sensors are introduced as well as electrical components including heating, energy storage and resistor devices.

Integrin signaling in cancer cell survival and chemoresistance

Resistance to apoptosis and chemotherapy is a hallmark of cancer cells, and it is a critical factor in cancer recurrence and patient relapse. Extracellular matrix (ECM) via its receptors, the integrins, has emerged as a major pathway contributing to cancer cell survival and resistance to chemotherapy. Several studies over the last decade have demonstrated that ECM/integrin signaling provides a survival advantage to various cancer cell types against numerous chemotherapeutic drugs and against antibody therapy. In this paper, we will discuss the major findings on how ECM/integrin signaling protects tumor cells from drug-induced apoptosis. We will also discuss the potential role of ECM in malignant T-cell survival and in cancer stem cell resistance. Understanding how integrins and their signaling partners promote tumor cell survival and chemoresistance will likely lead to the development of new therapeutic strategies and agents for cancer treatment.

The enhancement of cancer stem cell properties of MCF-7 cells in 3D collagen scaffolds for modeling of cancer and anti-cancer drugs

Three-dimensional (3D) culture could partially simulate in vivo conditions. In this work, we developed a 3D collagen scaffold to investigate cellular properties of MCF-7 cells. The porous scaffolds not only induced the diversification of cell morphologies but also extended cell proliferation. The expression of pro-angiogenic growth factors and the transcriptions of matrix metalloproteinases (MMPs) were significantly increased in cells cultured in 3D collagen scaffolds. In addition, 3D collagen scaffolds could generate a cell population with the properties of cancer stem cells (CSCs). The upregulation of EMT markers and the downregulation of the epithelial cell marker were observed in cells cultured in collagen scaffolds. The expression of stem cell markers, including OCT4A and SOX2, and breast cancer stem cell signatures, including SOX4, JAG1 and CD49F, was significantly unregulated in 3D collagen scaffolds. The proportion of cells with CSC-like CD44(+)/CD24(-/low) phenotype was notably increased. High-level expression of CSC-associated properties of MCF-7 cells cultured in 3D was further confirmed by high tumorigenicity in vivo. Moreover, xenografts with 3D cells formed larger tumors. The properties of MCF-7 cells in 3D may have partially simulated their in vivo behaviors. Thus, 3D collagen scaffolds might provide a useful platform for anti-cancer therapeutics and CSC research.

Therapeutic targeting of tumor-stroma interactions

INTRODUCTION

Cancers exist within a complex microenvironment populated by diverse cell types within a protein-rich extracellular matrix. It is becoming increasingly apparent that molecular interactions between epithelial cells and cells in the surrounding stroma promote growth, invasion and spread of the tumor itself and thus represents a crucial underlying driving force in tumorigenesis.

AREAS COVERED

This article reviews how key interactions between tumor epithelial cells and surrounding mesenchymal and immune cells can promote tumor progression and highlights molecular elements that might represent novel therapeutic targets.

EXPERT OPINION

The tumor microenvironment is increasingly being viewed as a potential therapeutic target with a number of strategies being developed to disrupt tumor-stroma interactions, in order to delay or circumvent tumor progression. Targeting elements of the tumor microenvironment, or signaling pathways in tumor cells activated as a consequence of stromal interactions, may prove a useful therapeutic strategy to prevent tumor development and progression. However, given the tumor cells' ability to circumvent various therapeutic agents when given as monotherapy, the success of these agents is likely to be seen when used in combination with existing treatments.