Targeting key steps in metastatic tumour progression

Investigation of tumour environments through advancements in microtechnology and nanotechnology

Cancer has a significant negative social and economic impact on both developed and developing countries. As a result, understanding the onset and progression of cancer is critical for developing therapies that can improve the well-being and health of individuals with cancer. With time, study has revealed, the tumor microenvironment has great influence on this process. Micro and nanoscale engineering techniques can be used to study the tumor microenvironment. Nanoscale and Microscale engineering use Novel technologies and designs with small dimensions to recreate the TME. Knowing how cancer cells interact with one another can help researchers develop therapeutic approaches that anticipate and counteract cancer cells' techniques for evading detection and fighting anti-cancer treatments, such as microfabrication techniques, microfluidic devices, nanosensors, and nanodevices used to study or recreate the tumor microenvironment. Nevertheless, a complicated action just like the growth and in cancer advancement, and their intensive association along the environment around it that has to be studied in more detail.

Recent Advances on Cell Culture Platforms for In Vitro Drug Screening and Cell Therapies: From Conventional to Microfluidic Strategies

The clinical translations of drugs and nanomedicines depend on coherent pharmaceutical research based on biologically accurate screening approaches. Since establishing the 2D in vitro cell culture method, the scientific community has improved cell-based drug screening assays and models. Those advances result in more informative biochemical assays and the development of 3D multicellular models to describe the biological complexity better and enhance the simulation of the in vivo microenvironment. Despite the overall dominance of conventional 2D and 3D cell macroscopic culture methods, they present physicochemical and operational challenges that impair the scale-up of drug screening by not allowing a high parallelization, multidrug combination, and high-throughput screening. Their combination and complementarity with microfluidic platforms enable the development of microfluidics-based cell culture platforms with unequivocal advantages in drug screening and cell therapies. Thus, this review presents an updated and consolidated view of cell culture miniaturization's physical, chemical, and operational considerations in the pharmaceutical research scenario. It clarifies advances in the field using gradient-based microfluidics, droplet-based microfluidics, printed-based microfluidics, digital-based microfluidics, SlipChip, and paper-based microfluidics. Finally, it presents a comparative analysis of the performance of cell-based methods in life research and development to achieve increased precision in the drug screening process.

Mg-based materials diminish tumor spreading and cancer metastases

Cancer metastases are the most common causes of cancer-related deaths. The formation of secondary tumors at different sites in the human body can impair multiple organ function and dramatically decrease the survival of the patients. In this stage, it is difficulty to treat tumor growth and spreading due to arising therapy resistances. Therefore, it is important to prevent cancer metastases and to increase subsequent cancer therapy success. Cancer metastases are conventionally treated with radiation or chemotherapy. However, these treatments elicit lots of side effects, wherefore novel local treatment approaches are currently discussed. Recent studies already showed anticancer activity of specially designed degradable magnesium (Mg) alloys by reducing the cancer cell proliferation. In this work, we investigated the impact of these Mg-based materials on different steps of the metastatic cascade including cancer cell migration, invasion, and cancer-induced angiogenesis. Both, Mg and Mg–6Ag reduced cell migration and invasion of osteosarcoma cells in coculture with fibroblasts. Furthermore, the Mg-based materials used in this study diminished the cancer-induced angiogenesis. Endothelial cells incubated with conditioned media obtained from these Mg and Mg–6Ag showed a reduced cell layer permeability, a reduced proliferation and inhibited cell migration. The tube formation as a last step of angiogenesis was stimulated with the presence of Mg under normoxia and diminished under hypoxia.

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Magnesium (Mg)-based material degradation decrease cell migration and invasion of an osteosarcoma coculture.

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Mg-based material degradation products reduce cancer-induced angiogenesis at an early stage.

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These materials may reduce secondary tumor formation and metastases.

PLC-gamma-1 phosphorylation status is prognostic of metastatic risk in patients with early-stage Luminal-A and -B breast cancer subtypes

Background

Phospholipase Cγ1 (PLCγ1) is highly expressed in human tumours. Our previous studies reported that both stable and inducible PLCγ1 down-regulation can inhibit formation of breast-cancer-derived experimental lung metastasis. Further, high expression of PLCγ1 and its constitutively activated forms (i.e., PLCγ1-pY1253, PLCγ1-pY783) is associated with worse clinical outcome in terms of incidence of distant metastases, but not of local relapse in T1-T2, N0 breast cancer patients.

Methods

In the present retrospective study, we analysed the prognostic role of PLCγ1 in early breast cancer patients stratified according to the St. Gallen criteria and to their menopausal status. PLCγ1-pY1253 and PLCγ1-pY783 protein expression levels were determined by immunohistochemistry on tissue microarrays, and were correlated with patients’ clinical data, using univariate and multivariate statistical analyses.

Results

In our series, the prognostic value of PLCγ1 overexpression was restricted to Luminal type tumours. From multivariate analyses, pY1253-PLCγ1^High was an independent prognostic factor only in postmenopausal patients with Luminal-B tumours (hazard ratio [HR], 2.4; 95% confidence interval [CI], 1.1–5.3; P = 0.034). Conversely, PLCγ1-pY783^High was a remarkably strong risk factor (HR, 20.1; 95% CI, 2.2–178.4; P = 0.003) for pre/perimenopausal patients with Luminal-A tumours.

Conclusions

PLCγ1 overexpression is a strong predictive surrogate marker of development of metastases in early Luminal-A and -B breast cancer patients, being able to discriminate patients with high and low risk of metastases. Therefore, targeting the PLCγ1 pathway can be considered of potential benefit for prevention of metastatic disease.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5949-x) contains supplementary material, which is available to authorized users.

Microfluidic modelling of the tumor microenvironment for anti-cancer drug development

Cancer is the leading cause of death worldwide. The complex and disorganized tumor microenvironment makes it very difficult to treat this disease. The most common in vitro drug screening method now is based on 2D culture models which poorly represent actual tumors. Therefore, many 3D tumor models which are more physiologically relevant have been developed to conduct in vitro drug screening and alleviate this situation. Among all these models, the microfluidic tumor model has the unique advantage of recapitulating the tumor microenvironment in a comparatively easier and representative fashion. While there are many review papers available on the related topic of microfluidic tumor models, in this review we aim to focus more on the possibility of generating "clinically actionable information" from these microfluidic systems, besides scientific insight. Our topics cover the tumor microenvironment, conventional 2D and 3D cultures, animal models, and microfluidic tumor models, emphasizing their link to anti-cancer drug discovery and personalized medicine.

Systems for localized release to mimic paracrine cell communication in vitro

Paracrine cell communication plays a pivotal role for signal exchange between proximal cells in vivo. However, this localized, gradient type release of mediators at very low concentrations (pg/ml), relevant during physiological and pathological processes, is rarely reflected within in vitro approaches. This review gives an overview on state-of-the-art approaches, which transfer the paracrine cell-to-cell communication into in vitro cell culture model setups. The traditional methods like trans-well assays and more advanced microfluidic approaches are included. The review focusses on systems for localized release, mostly based on microparticles, which tightly mimic the paracrine interaction between single cells in 3D microenvironments. Approaches based on single microparticles, with the main focus on affinity-controlled storage and release of cytokines, are reviewed and their importance for understanding paracrine communication is highlighted. Various methods to study the cytokine release and their advantages and disadvantages are discussed. Basic principles of the release characteristics, like diffusion mechanisms, are quantitatively described, including the formation of resulting gradients around the local sources. In vitro cell experiments using such localized microparticle release systems in approaches to increase understanding of stem cell behavior within their niches and regulation of wound healing are highlighted as examples of successful localized release systems for mimicking paracrine cell communication.

Mimicking Embedded Vasculature Structure for 3D Cancer on a Chip Approaches through Micromilling

The ability for cells to sense and respond to microenvironmental signals is influenced by their three dimensional (3D) surroundings, which includes the extracellular matrix (ECM). In the 3D environment, vascular structures supply cells with nutrients and oxygen thus affecting cell responses such as motility. Interpretation of cell motility studies though is often restricted by the applied approaches such as 2D conventional soft lithography methods that have rectangular channel cross-sectional morphology. To better simulate cell responses to vascular supply in 3D, we developed a cell on a chip system with microfluidic channels with curved cross-sections embedded within a 3D collagen matrix that emulates anatomical vasculature more closely than inorganic polymers, thus to mimic a more physiologically relevant 3D cellular environment. To accomplish this, we constructed perfusable microfluidic channels by embedding sacrificial circular gelatin vascular templates in collagen, which were removed through temperature control. Motile breast cancer cells were pre-seeded into the collagen matrix and when presented with a controlled chemical stimulation from the artificial vasculature, they migrated towards the vasculature structure. We believe this innovative vascular 3D ECM system can be used to provide novel insights into cellular dynamics during multidirectional chemokineses and chemotaxis that exist in cancer and other diseases.

The lichen secondary metabolite atranorin suppresses lung cancer cell motility and tumorigenesis

Lichens are symbiotic organisms that produce various secondary metabolites. Here, different lichen extracts were examined to identify secondary metabolites with anti-migratory activity against human lung cancer cells. Everniastrum vexans had the most potent inhibitory activity, and atranorin was identified as an active subcomponent of this extract. Atranorin suppressed β-catenin-mediated TOPFLASH activity by inhibiting the nuclear import of β-catenin and downregulating β-catenin/LEF and c-jun/AP-1 downstream target genes such as CD44, cyclin-D1 and c-myc. Atranorin decreased KAI1 C-terminal interacting tetraspanin (KITENIN)-mediated AP-1 activity and the activity of the KITENIN 3′-untranslated region. The nuclear distribution of the AP-1 transcriptional factor, including c-jun and c-fos, was suppressed in atranorin-treated cells, and atranorin inhibited the activity of Rho GTPases including Rac1, Cdc42, and RhoA, whereas it had no effect on epithelial-mesenchymal transition markers. STAT-luciferase activity and nuclear STAT levels were decreased, whereas total STAT levels were moderately reduced. The human cell motility and lung cancer RT² Profiler PCR Arrays identified additional atranorin target genes. Atranorin significantly inhibited tumorigenesis in vitro and in vivo. Taken together, our results indicated that E. vexans and its subcomponent atranorin may inhibit lung cancer cell motility and tumorigenesis by affecting AP-1, Wnt, and STAT signaling and suppressing RhoGTPase activity.

Peptidomimetic inhibitors of APC-Asef interaction block colorectal cancer migration

The binding of adenomatous polyposis coli (APC) to its receptor Asef relieves the negative intramolecular regulation of Asef and leads to aberrant cell migration in human colorectal cancer. Because of its crucial role in metastatic dissemination, the interaction between APC and Asef is an attractive target for anti-colorectal-cancer therapy. We rationally designed a series of peptidomimetics that act as potent inhibitors of the APC interface. Crystal structures and biochemical and cellular assays showed that the peptidomimetics in the APC pocket inhibited the migration of colorectal cells by disrupting APC-Asef interaction. By using the peptidomimetic inhibitor as a chemical probe, we found that CDC42 was the downstream GTPase involved in APC-stimulated Asef activation in colorectal cancer cells. Our work demonstrates the feasibility of exploiting APC-Asef interaction to regulate the migration of colorectal cancer cells, and provides what to our knowledge is the first class of protein-protein interaction inhibitors available for the development of cancer therapeutics targeting APC-Asef signaling.

3D bioprinting: improving in vitro models of metastasis with heterogeneous tumor microenvironments

Even with many advances in treatment over the past decades, cancer still remains a leading cause of death worldwide. Despite the recognized relationship between metastasis and increased mortality rate, surprisingly little is known about the exact mechanism of metastatic progression. Currently available in vitro models cannot replicate the three-dimensionality and heterogeneity of the tumor microenvironment sufficiently to recapitulate many of the known characteristics of tumors in vivo Our understanding of metastatic progression would thus be boosted by the development of in vitro models that could more completely capture the salient features of cancer biology. Bioengineering groups have been working for over two decades to create in vitro microenvironments for application in regenerative medicine and tissue engineering. Over this time, advances in 3D printing technology and biomaterials research have jointly led to the creation of 3D bioprinting, which has improved our ability to develop in vitro models with complexity approaching that of the in vivo tumor microenvironment. In this Review, we give an overview of 3D bioprinting methods developed for tissue engineering, which can be directly applied to constructing in vitro models of heterogeneous tumor microenvironments. We discuss considerations and limitations associated with 3D printing and highlight how these advances could be harnessed to better model metastasis and potentially guide the development of anti-cancer strategies.

Concentration gradient generator for H460 lung cancer cell sensitivity to resist the cytotoxic action of curcumin in microenvironmental pH conditions

We proposed and demonstrated a concentration gradient generator (CGG) to resist H460 lung cancer cells using curcumin in microenvironmental pH conditions.

Surface protein gradients generated in sealed microchannels using spatially varying helium microplasma

Spatially varied surface treatment of a fluorescently labeled Bovine Serum Albumin (BSA) protein, on the walls of a closed (sealed) microchannel is achieved via a well-defined gradient in plasma intensity. The microchips comprised a microchannel positioned in-between two microelectrodes (embedded in the chip) with a variable electrode separation along the length of the channel. The channel and electrodes were 50 μm and 100 μm wide, respectively, 50 μm deep, and adjacent to the channel for a length of 18 mm. The electrode separation distance was varied linearly from 50 μm at one end of the channel to a maximum distance of 150, 300, 500, or 1000 μm to generate a gradient in helium plasma intensity. Plasma ignition was achieved at a helium flow rate of 2.5 ml/min, 8.5 kVpk-pk, and 10 kHz. It is shown that the plasma intensity decreases with increasing electrode separation and is directly related to the residual amount of BSA left after the treatment. The plasma intensity and surface protein gradient, for the different electrode gradients studied, collapse onto master curves when plotted against electrode separation. This precise spatial control is expected to enable the surface protein gradient to be tuned for a range of applications, including high-throughput screening and cell-biomolecule-biomaterial interactions.

Polymer-controlled core–shell nanoparticles: a novel strategy for sequential drug release

Immiscible and miscible liquids were utilized to fabricate PVP/PLGA and PCL/PLGA nanoparticles with a distinct core–shell structure by coaxial electrospray. Two different sequential drug release profiles from different nanoparticles were observed. The melanoma cells and endothelial cells can be sequentially targeted and killed by therapeutic agents released from nanoparticles.

Patterning microscale extracellular matrices to study endothelial and cancer cell interactions in vitro

The extracellular matrix (ECM) of the tumor niche provides support to residing and migrating cells and presents instructive cues that influence cellular behaviours. The ECM protein fibronectin (Fn) enables vascular network formation, while hyaluronic acid (HA) is known to facilitate breast tumor development. To recapitulate aspects of the tumor microenvironment, we developed systems of spatially defined Fn and HA for the co-culture of endothelial colony forming cells (ECFCs) and breast cancer cells (BCCs). A micropatterned system was developed using sequential microcontact printing of HA and Fn. This approach supported the preferential adhesion of ECFCs to Fn, but did not support the preferential adhesion of BCCs to HA. Thus, we developed a microstructured analog to spatially organize BCC-laden HA micromolded hydrogels adjacent to ECFCs in fibrin hydrogels. These novel, miniaturized systems allow the analysis of the spatial and temporal mechanisms regulating tumor angiogenesis, and can be applied to mimic other microenvironments of healthy and diseased tissues.

Overexpression of activated phospholipase Cγ1 is a risk factor for distant metastases in T1-T2, N0 breast cancer patients undergoing adjuvant chemotherapy

Phospholipase Cγ1 (PLCγ1) is highly expressed in several tumors. We have previously reported that both stable and inducible PLCγ1 down-regulation resulted in an almost complete inhibition of breast cancer-derived experimental lung metastasis formation. The aim of our study is to evaluate the association between the expression of PLCγ1 and of PLCγ1 phosphorylated at Tyr1253 (PLCγ1-pY1253) and at Tyr783 (PLCγ1-pY783) with the clinical outcome of patients with node negative, T1/T2 breast cancers. The study groups consisted of 292 (training set) and 122 (validation set) patients presenting with primary unilateral breast carcinoma (T1-T2), with no evidence of nodal involvement and distant metastases. PLCγ1, PLCγ1-pY1253 and PLCγ1-pY783 protein expression were assessed by immunohistochemistry on tissue microarrays and the results correlated with the clinical data using Kaplan-Meier curves and multivariate Cox regression analysis. Tumor cells while expressing variable proportions of cytoplasmic PLCγ1, express PLCγ1-pY1253 and PLCγ1-pY783 predominantly in the nucleus. High expression of PLCγ1, and of its activated forms, is associated with a worse clinical outcome in terms of incidence of distant metastases, and not of local relapse in T1-T2, N0 breast cancer patients undergone adjuvant chemotherapy. PLCγ1 over-expression appears to be a reliable predictive surrogate marker of development of metastases. Thus, targeting PLCγ1 pathways might represent a potential therapeutic approach for the prevention of metastatic disease in breast cancer.

The effect of PLC-γ2 inhibitors on the growth of human tumour cells

The phosphoinositide specific-phospholipase C-γ (PLC-γ1 and 2) enzymes are plausible anticancer targets implicated in cell motility important to invasion and dissemination of tumour cells. A host of known PLC-γ2 inhibitors were tested against the NCI60 panel of human tumour cell lines as well as their commercially available structural derivatives. A class of thieno[2,3-b]pyridines showed excellent growth arrest with derivative 3 giving GI(50) = 58 nM for the melanoma MDA-MB-435 cell line. The PLC-γ2 is uniquely expressed in haematopoietic cells and the leukaemia tumour cell lines were growth restricted on average GI(50) = 275 nM by derivative 3 indicating a specific interaction with this isoform. Furthermore, a moderate growth inhibition was found for compound classes of indoles and 1H-pyrazoles. It is likely that the active compounds do not only inhibit the PLC-γ2 isoform but other PLCs as well due to their conserved binding site. The compounds tested were identified by applying the tools of chemoinformatics, which supports the use of in silico methods in drug design.

Versatile gradients of chemistry, bound ligands and nanoparticles on alumina nanopore arrays

Nanoporous alumina (PA) arrays produced by self-ordering growth, using electrochemical anodization, have been extensively explored for potential applications based upon the unique thermal, mechanical and structural properties, and high surface-to-volume ratio of these materials. However, the potential applications and functionality of these materials may be further extended by molecular-level engineering of the surface of the pore rims. In this paper we present a method for the generation of chemical gradients on the surface of PA arrays based upon plasma co-polymerization of two monomers. We further extend these chemical gradients, which are also gradients of surface charge, to those of bound ligands and number density gradients of nanoparticles. The latter represent a highly exotic new class of materials, comprising aligned PA, capped by gold nanoparticles around the rim of the pores. Gradients of chemistry, ligands and nanoparticles generated by our method retain the porous structure of the substrate, which is important in applications that take advantage of the inherent properties of these materials. This method can be readily extended to other porous materials.

1,25-Dihydroxyvitamin D(3) regulates PTHrP expression via transcriptional, post-transcriptional and post-translational pathways

Parathyroid hormone-related protein (PTHrP) increases the growth and osteolytic potential of prostate cancer cells, making it important to control PTHrP expression. PTHrP expression is suppressed by 1,25-dihydroxyvitamin D(3) (1,25D). The aim of this study was to identify the pathways via which 1,25D exerts these effects. Our main findings are that 1,25D regulates PTHrP levels via multiple pathways in PC-3 and C4-2 (human prostate cancer) cell lines, and regulation is dependent on VDR expression. The human PTHrP gene has three promoters (P); PC-3 cells preferentially utilize P2 and P3, while C4-2 cells preferentially utilize P1. 1,25D regulates PTHrP transcriptional activity from both P1 and P3. The 1,25D-mediated decrease in PTHrP mRNA levels also involves a post-transcriptional pathway since 1,25D decreases PTHrP mRNA stability. 1,25D also suppresses PTHrP expression directly at the protein level by increasing its degradation. Regulation of PTHrP levels is dependent on VDR expression, as using siRNAs to deplete VDR expression negates the 1,25D-mediated downregulation of PTHrP expression. These results indicate the importance of maintaining adequate 1,25D levels and VDR status to control PTHrP levels.

Creating growth factor gradients in three dimensional porous matrix by centrifugation and surface immobilization

Polycaprolactone (PCL)/Pluronic F127 cylindrical scaffolds with gradually increasing growth factor concentrations were fabricated by the centrifugation of fibril-like PCLs and the subsequent fibril surface immobilization of growth factors. The cylindrical scaffolds exhibited gradually increasing surface areas along the longitudinal direction [from 3.17 ± 0.05 m(2)/g (top position) to 5.42 ± 0.01 m(2)/g (bottom position)]. The growth factors (BMP-7, TGF-β(2) and VEGF(165)) as model bioactive molecules were immobilized onto the fibril surfaces of the scaffolds via heparin binding to produce scaffolds with gradually increasing concentrations of growth factors from the top position (BMP-7, 60.89 ± 2.51; TGF-β(2), 42.85 ± 2.00; VEGF(165), 42.52 ± 3.22 ng/scaffold section) to the bottom position (BMP-7, 181.07 ± 3.21; TGF-β(2), 142.08 ± 2.91; VEGF(165), 112.00 ± 4.00 ng/scaffold section). The released amount of growth factor (VEGF(165)) from the cylindrical scaffold gradually decreased along the longitudinal direction in a sustained manner for up to 35 days, which can allow for a minutely controlled spatial distribution of growth factors in a 3D environment. The 3D porous scaffold with a concentration gradient of growth factors may become a useful tool for basic studies, including in vitro investigations of 3D chemotaxis/haptotaxis for the control of specific biological process. It may also be used as a tissue engineering scaffolding system for a variety of tissues/organs requiring the spatial regulation of growth factors for effective regeneration.

Role of SOCS-1 Gene on Melanoma Cell Growth and Tumor Development

Melanoma is the most aggressive form of skin cancer, and its incidence has increased dramatically over the years. The murine B16F10 melanoma in syngeneic C57Bl/6 mice has been used as a highly aggressive model to investigate tumor development. Presently, we demonstrate in the B16F10-Nex2 subclone that silencing of SOCS-1, a negative regulator of Jak/Stat pathway, leads to reversal of the tumorigenic phenotype and inhibition of melanoma cell metastasis. SOCS-1 silencing with short hairpin RNA affected tumor growth and cell cycle regulation with arrest at the S phase with large-sized nuclei, reduced cell motility, and decreased melanoma cell invasion through Matrigel. A clonogenic assay showed that SOCS-1 acted as a modulator of resistance to anoikis. In addition, downregulation of SOCS-1 decreased the expression of epidermal growth factor receptor (mainly the phosphorylated-R), Ins-Rα, and fibroblast growth factor receptor. In vivo, silencing of SOCS-1 inhibited subcutaneous tumor growth and metastatic development in the lungs. Because SOCS-1 is expressed in most melanoma cell lines and bears a relation with tumor invasion, thickness, and stage of disease, the present results on the effects of SOCS-1 silencing in melanoma suggest that this regulating protein can be a target of cancer therapy.

Predicting invasive phenotype with CDH1, CDH13, CD44, and TIMP3 gene expression in primary breast cancer

We aimed to determine changes in the expression of the genes CDH1, CDH13, CD44, and TIMP3 to look for any relationship between them, HER2 and ESR1 expression at the RNA level, and the histopathological properties of tumors. We also analyzed the expression properties of double-negative (estrogen receptor [ER] and human epidermal growth factor receptor [HER2] both negative) breast tumors. Expression status was studied in fresh tissue at the mRNA level with quantitative PCR using hydrolysis probes. Sixty-two cancer patients and four normal controls were included in the study. When the tumor group was analyzed as a whole, the correlations of ESR1 with CDH1, CDH13, and TIMP3 were P < 0.05, P < 0.005, and P < 0.005, respectively. In ER-positive tumors, CDH1 and CDH13 were correlated directly (P < 0.005) when HER2 was correlated with CDH1, CDH13, and TIMP3 indirectly (P < 0.005, P < 0.005, and P < 0.05, respectively). CDH1 and CD44 had a strong indirect correlation (P < 0.005) in ER-negative tumors. There were significant differences in the expression levels of the CDH13, TIMP3, and CD44 genes (P < 0.005, P < 0.005, and P < 0.05, respectively) between the ER-positive and -negative groups. All four genes were found to be correlated with invasive properties in both ER-positive and -negative tumors. In double-negative tumor samples, only CD44 had a significant and strong correlation with stage, lymph node involvement, and metastasis (P < 0.05, P < 0.005, and P < 0.05, respectively). As a conclusion, a decrease in CDH1, CDH13, and TIMP3 expression levels with an increase in CD44 can be used as an indicator for invasion in both ER-positive and -negative breast tumors. In double-negative tumor tissues, CD44 can be considered a marker for aggressive properties.

Recent advances in multivalent self adjuvanting glycolipopeptide vaccine strategies against breast cancer

Breast cancer (BrCa) is the second leading cause of cancer-related deaths for women worldwide. Evidence from both patients and mouse cancer models suggests that the simultaneous induction of BrCa-specific CD4(+) T cells, CD8(+) cytotoxic T cells, and antibodies is crucial for providing immune resistance. However, almost all current vaccines address only a single arm of the immune system, which may explain their lack of efficacy. We believe that the correct response to monovalent vaccines' "failure" is to increase our knowledge about antitumor protective immunity and to develop a multivalent vaccine molecule that can simultaneously induce multiple arms of the immune system. We highlight here recent advances in anti-BrCa peptide-based vaccine strategies with an emphasis on the self adjuvanting multivalent glycolipopeptide vaccine strategy recently developed in our laboratory and which showed promising results in both immunotherapeutic and immunoprophylactic settings.

Oral cancer cells with different potential of lymphatic metastasis displayed distinct biologic behaviors and gene expression profiles

OBJECTIVE

Oral squamous cell carcinoma (OSCC) often spreads from the primary tumor to regional lymph nodes in the early stage. Better understanding of the biology of lymphatic spread of oral cancer cells is important for improving the survival rate of cancer patients.

METHODS

We established the cell line LNMTca8113 by repeated injections in foot pads of nude mice, which had a much higher lymphatic metastasis rate than its parental cell line Tca8113. Then, we compared the biologic behaviors of cancer cells between them. Moreover, microarray-based expression profiles between them were also compared, and a panel of differential genes was validated using real-time-PCR.

RESULTS

In contrast to Tca8113 cells, LNMTca8113 cells were more proliferative and resistant to apoptosis in the absence of serum, and had enhanced ability of inducing capillary-like structures. Moreover, microarray-based expression profiles between them identified 1341 genes involved in cell cycle, cell adhesion, lymphangiogenesis, regulation of apoptosis, and so on. Some genes dedicating to the metastatic potential, including JAM2, TNC, CTSC, LAMB1, VEGFC, HAPLN1, ACPP, GDF9 and FGF11, were upregulated in LNMTca8113 cells.

CONCLUSION

These results suggested that LNMTca8113 and Tca8113 cells were proper models for lymphatic metastasis study because there were differences in biologic behaviors and metastasis-related genes between them. Additionally, the differentially expressed gene profiles in cancer progression may be helpful in exploring therapeutic targets and provide the foundation for further functional validation of these specific candidate genes for OSCC.

EB1089 inhibits the parathyroid hormone-related protein-enhanced bone metastasis and xenograft growth of human prostate cancer cells

Parathyroid hormone-related protein (PTHrP) plays a major role in prostate carcinoma progression and bone metastasis. Once prostate cancers become androgen-independent, treatment options become limited. Vitamin D analogues represent a potentially valuable class of agents in this clinical context. Using the prostate cancer cell line C4-2 as a model, we studied the effects of PTHrP and the noncalcemic vitamin D analogue EB1089 on markers of prostate cancer cell progression in vitro and in vivo. C4-2 is a second-generation androgen-independent LNCaP subline that metastasizes to the lymph nodes and bone when injected into nude mice and produces mixed lytic/blastic lesions, mimicking the in vivo situation. We report that PTHrP increases cell migration and invasion, and that a pathway via which EB1089 inhibits these processes is through down-regulation of PTHrP expression. PTHrP also increases anchorage-independent cell growth in vitro and xenograft growth in vivo; EB1089 reverses these effects. The in vivo PTHrP effects are accompanied by increased tumor cell proliferation and survival. Treatment with EB1089 reverses the proliferative but not the antiapoptotic effects of PTHrP. PTHrP also increases intratumor vessel density and vascular endothelial growth factor expression; EB1089 reverses these effects. Intracardially injected C4-2 cells produce predominantly osteoblastic lesions; PTHrP overexpression decreases the latency, increases the severity and alters the bone lesion profile to predominantly osteolytic. EB1089 largely reverses these PTHrP effects. A direct correlation between PTHrP immunoreactivity and increasing tumor grade is observed in human prostate cancer specimens. Thus, decreasing PTHrP production by treatment with vitamin D analogues may prove therapeutically beneficial for prostate cancer.

Changes in choline metabolism as potential biomarkers of phospholipase C{gamma}1 inhibition in human prostate cancer cells

Phosphoinositide-specific phospholipase Cγ1 (PLCγ1) is activated downstream of many receptor tyrosine kinases to promote cell motility. Inhibition of this protein is being explored as a therapeutic strategy for blocking cancer cell invasion and metastasis. The clinical development of such cytostatic therapies requires the implementation of pharmacodynamic biomarkers of target modulation. In this study, we use magnetic resonance spectroscopy to explore metabolic biomarkers of PLCγ1 down-regulation in PC3LN3 prostate cancer cells. We show that inhibition of PLCγ1 via an inducible short hairpin RNA system causes a reduction in phosphocholine levels by up to 50% relative to the control as detected by (1)H and (31)P magnetic resonance spectroscopy analyses. This correlated with a rounded-up morphology and reduced cell migration. Interestingly, the fall in phosphocholine levels was not recorded in cells with constitutive PLCγ1 knockdown where the rounded-up phenotype was no longer apparent. This study reveals alterations in metabolism that accompany the cellular effects of PLCγ1 knockdown and highlights phosphocholine as a potential pharmacodynamic biomarker for monitoring the action of inhibitors targeting PLCγ1 signaling.

Effect of pro-inflammatory cytokine stimulation on human breast cancer: implications of chemokine receptor expression in cancer metastasis

Interactions between tumour cells and microenvironments may affect their growth and metastasis formation. In search for a better understanding of the role of cellular mediators in the progression of cancer, we investigated the effect of pro-inflammatory cytokines IL-1, IL-6, TNF-alpha and IFN-gamma on the regulation of expression of chemokine receptors CXCR4, CXCR2, CX3CR1, CCR9, and CCR5 in the human breast cancer cell line MCF-7. Our results showed that IL-1 increased CXCR4 expression whereas TNF-alpha increased CX3CR1, CCR9 and CCR5. Interestingly, this regulation was not homogeneous, emphasizing the inherent heterogeneity in cancer that may be responsive to specific inflammatory microenvironments.

Computational modelling suggests dynamic interactions between Ca2+, IP3 and G protein-coupled modules are key to robust Dictyostelium aggregation

Under conditions of starvation, Dictyostelium cells begin a programme of development during which they aggregate to form a multicellular structure by chemotaxis, guided by propagating waves of cyclic AMP that are relayed robustly from cell to cell. In this paper, we develop and analyse a new model for the intracellular and extracellular cAMP dependent processes that regulate Dictyostelium migration. The model allows, for the first time, a quantitative analysis of the dynamic interactions between calcium, IP(3) and G protein-dependent modules that are shown to be key to the generation of robust cAMP oscillations in Dictyostelium cells. The model provides a mechanistic explanation for the transient increase in cytosolic free Ca(2+) concentration seen in recent experiments with the application of the calmodulin inhibitor calmidazolium (R24571) to Dictyostelium cells, and also allows elucidation of the effects of varying both the conductivity of stretch-activated channels and the concentration of external phosphodiesterase on the oscillatory regime of an individual cell. A rigorous analysis of the robustness of the new model shows that interactions between the different modules significantly reduce the sensitivity of the resulting cAMP oscillations to variations in the kinetics of different Dictyostelium cells, an essential requirement for the generation of the spatially and temporally synchronised chemoattractant cAMP waves that guide Dictyostelium aggregation.

ArgBP2 and the SoHo family of adapter proteins in oncogenic diseases

ArgBP2, a member of the SoHo family of adapter proteins, is a regulator of actin-dependent processes such as cell adhesion and migration. Recent data from our lab revealed that by regulating adhesion and migration of pancreatic cancer cells, ArgBP2 is endowed with an anti-tumoral function. We could show that part of the molecular mechanism involved the interaction of ArgBP2 with the Arp2/3 activator WAVE1, the tyrosine phosphatase PTP-PEST, and the tyrosine kinase c-Abl. As ArgBP2 shares common structural organization and overlapping functions with the two other members of this protein family, CAP and Vinexin, it raises the question whether these two other proteins could also be involved in cancer diseases. The control of cell migration being an important issue in tumor treatment, these recent findings suggest that ArgBP2 family-dependent signaling pathways represents potential targets for the development of therapeutic strategies, and highlight the importance of elucidating their molecular mechanisms of cytoskeletal regulation.

The identification of novel PLC-gamma inhibitors using virtual high throughput screening

Phospholipase C-gamma (PLC-gamma) has been identified as a possible biological target for anticancer drug therapy but suitable inhibitors are lacking. Therefore, in order to identify active compounds (hits) virtual high throughput screening was performed. The crystal structure of the PLC-delta isoform was used as a model docking scaffold since no crystallographic data are available on its gamma counterpart. A pilot screen was performed using approximately 9.2x10(4) compounds, where the robustness of the methodology was tested. This was followed by the main screening effort where approximately 4.4x10(5) compounds were used. In both cases, plausible compounds were identified (virtual hits) and a selection of these was experimentally tested. The most potent compounds were in the single digit micro-molar range as determined from the biochemical (Flashplate) assay. This translated into approximately 15 microM in a functional assay in cells. About 30% of the virtual hits showed activity against PLC-gamma (IC(50)<50 microM).

Decreased metastatic phenotype in cells resistant to aminolevulinic acid-photodynamic therapy

Photodynamic therapy (PDT) is a novel cancer treatment utilising a photosensitiser, visible light and oxygen. PDT often leaves a significant number of surviving tumour cells. In a previous work, we isolated and studied two PDT resistant clones derived from the mammary adenocarcinoma LM3 line (Int. J. Oncol. 29 (2006) 397-405). The isolated Clon 4 and Clon 8 exhibited a more fibroblastic, dendritic pattern and were larger than the parentals. In the present work we studied the metastatic potential of the two clones in comparison with LM3. We found that 100% of LM3 invaded Matrigel, whereas only 19+/-6% and 24+/-7% of Clon 4 and Clon 8 cells invaded. In addition, 100% of LM3 cells migrated towards a chemotactic stimulus whereas 38+/-8% and 73+/-10% of Clones 4 and 8, respectively, were able to migrate. In vivo, 100% of the LM3 injected mice developed spontaneous lung metastasis, whereas none of the Clon 8 did, and only one of the mice injected with Clon 4 did. No differences were found in the proteolytic enzyme profiles among the cells. Anchorage-dependent adhesion was also impaired in vivo in the resistant clones, evidenced by the lower tumour take, latency time and growth rates, although both clones showed in vitro higher binding to collagen I without overexpression of beta1 integrin. This is the first work where the metastatic potential of cells surviving to PDT has been studied. PDT strongly affects the invasive phenotype of these cells, probably related to a higher binding to collagen. These findings may be crucial for the outcome of ALA-PDT of metastatic tumours, although further studies are needed to extrapolate the results to the clinic employing another photosensitisers and cell types.

Highlighting the role of Ras and Rap during Dictyostelium chemotaxis

Chemotaxis, the directional movement towards a chemical compound, is an essential property of many cells and has been linked to the development and progression of many diseases. Eukaryotic chemotaxis is a complex process involving gradient sensing, cell polarity, remodelling of the cytoskeleton and signal relay. Recent studies in the model organism Dictyostelium discoideum have shown that chemotaxis does not depend on a single molecular mechanism, but rather depends on several interconnecting pathways. Surprisingly, small G-proteins appear to play essential roles in all these pathways. This review will summarize the role of small G-proteins in Dictyostelium, particularly highlighting the function of the Ras subfamily in chemotaxis.

Biomolecular gradients in cell culture systems

Biomolecule gradients have been shown to play roles in a wide range of biological processes including development, inflammation, wound healing, and cancer metastasis. Elucidation of these phenomena requires the ability to expose cells to biomolecule gradients that are quantifiable, controllable, and mimic those that are present in vivo. Here we review the major biological phenomena in which biomolecule gradients are employed, traditional in vitro gradient-generating methods developed over the past 50 years, and new microfluidic devices for generating gradients. Microfluidic gradient generators offer greater levels of precision, quantitation, and spatiotemporal gradient control than traditional methods, and may greatly enhance our understanding of many biological phenomena. For each method, we outline the salient features, capabilities, and applications.

Lymphatic metastasis in breast cancer: importance and new insights into cellular and molecular mechanisms

Lymph node metastasis is the main prognosis factor in a number of malignancies, including breast carcinomas. The means by which lymph node metastases arise is not fully understood, and many questions remain about their importance in the further spread of breast cancer. Nevertheless, a number of key cellular and molecular mechanisms of lymphatic metastasis have been identified. These include induction of intra- or peri-tumoral lymphangiogenesis or co-option of existing lymphatic vessels to allow tumour cells to enter the lymphatics, although it remains to be established whether this is primarily an active or passive process. Gene expression microarrays and functional studies in vitro and in vivo, together with detailed clinical observations have identified a number of molecules that can play a role in the genesis of lymph node metastases. These include the well-recognised lymphangiogenic cytokines VEGF-C and VEGF-D as well as chemokine-receptor interactions, integrins and downstream signalling pathways. This paper briefly reviews current clinical and experimental evidence for the underlying mechanisms and significance of lymphatic metastasis in breast cancer and highlights questions that still need to be addressed.

Syk tyrosine kinase is linked to cell motility and progression in squamous cell carcinomas of the head and neck

Syk, a non-receptor tyrosine kinase, is an important component of immunoreceptor signaling in hematopoietic cells. It has been implicated in key regulatory pathways including phosphoinositide 3-kinase and phospholipase Cgamma (PLCgamma) activation in B cells and integrin signaling in platelets and bronchial epithelial cells. Recently, potential roles in cancer have been reported. In breast cancers, reduced Syk expression was associated with invasion, and its overexpression in cell lines was shown to inhibit cell motility. In contrast, Syk has been shown to mediate chemomigration in nasopharyngeal carcinoma cells. Its role in squamous cell carcinomas of the head and neck (SCCHN) has not yet been investigated. Syk mRNA and protein expression was detected in 6 of 10 SCCHN cell lines. When Syk was transfected into Syk-negative cells (SIHN-011A), chemomigration was enhanced in vitro and this was associated with activation of PLCgamma1. Conversely, abrogation of Syk activity by pharmacologic inhibition or small interfering RNA in HN6 cells with high levels of endogenous expression inhibited migration, haptotaxis, and engagement with matrix proteins; this was accompanied by decreased levels of phosphorylated AKT. Similar effects were seen in Syk-positive CAL 27 cells but not in Syk-negative SIHN-011A cells. Immunoprecipitation suggested co-association of Syk with epidermal growth factor receptor and GRB-2. Syk expression in SCCHN patient tissues was examined by semiquantitative real-time PCR (n = 45) and immunohistochemistry (n = 38) in two independent cohorts. Higher levels of Syk expression were observed in tumors and lymph node metastases relative to normal tissues. High Syk expression significantly correlated with worse survival and may be of prognostic value in SCCHN due to its potential role in cell migration and invasion.

A convenient clinically relevant model of human breast cancer bone metastasis

Breast cancer patients with advanced disease exhibit bone metastases, leading to the formation of osteolytic lesions for which the only currently available treatments are palliative. Here, we describe how we refined a mouse model of human breast cancer metastasis into bone, characterized its transcriptome and demonstrated its clinical relevance. Cells were selected from bone metastases caused by MDA-MB-231 cells after several in vivo passages, and engineered to express luciferase. Whole body bioluminescence live imaging indicated that the selected isogenic B02 clone was unique in its ability to form rapidly growing osteolytic bone metastases. B02 cells were detected as early as 10 days after tail vein injection, as opposed to 1 month after cardiac injection in other haematogenous models. Whole transcriptomic analysis identified 114 upregulated and 247 downregulated genes in B02 cells compared to the parental cells, several of which represent novel targets. In addition, there was a 50% overlap between the B02 signature and a recently described signature obtained from human breast cancer bone metastases. Consistent with the plasticity of an aggressive metastatic variant, 10% of the regulated genes are involved in proliferation, migration, invasion and angiogenesis. Strikingly, B02 cells also express osteoblast-specific genes, thus mimicking a process referred to as osteomimicry in the clinic. The B02 cells "human bone metastatic signature", the expression of bone-specific genes, as well as the live imaging of this convenient model highlight its clinical relevance and usefulness during drug development.

Modeling the proteome of a Marek's disease transformed cell line: a natural animal model for CD30 overexpressing lymphomas

Marek's disease (MD) in the chicken, caused by the highly infectious MD alpha-herpesvirus (MDV), is both commercially important and a unique, naturally occurring model for human T-cell lymphomas overexpressing the Hodgkin's disease antigen, CD30. Here, we used proteomics as a basis for modeling the molecular functions and biological processes involved in MDV-induced lymphomagenesis. Proteins were extracted from an MDV-transformed cell line and were then identified using 2-D LC-ESI-MS/MS. From the resulting 3870 cellular and 21 MDV proteins we confirm the existence of 3150 "predicted" and 12 "hypothetical" chicken proteins. The UA-01 proteome is proliferative, differentiated, angiogenic, pro-metastatic and pro-immune-escape but anti-programmed cell death, -anergy, -quiescence and -senescence and is consistent with a cancer phenotype. In particular, the pro-metastatic integrin signaling pathway and the ERK/MAPK signaling pathways were the two predominant signaling pathways represented. The cytokines, cytokine receptors, and their related proteins suggest that UA-01 has a regulatory T-cell phenotype.

Signaling pathways mediating chemotaxis in the social amoeba, Dictyostelium discoideum

Chemotaxis, or cell migration guided by chemical cues, is critical for a multitude of biological processes in a diverse array of organisms. Dictyostelium discoideum amoebae rely on chemotaxis to find food and to survive starvation conditions, and we have taken advantage of this system to study the molecular regulation of this vital cell behavior. Previous work has identified phosphoinositide signaling as one mechanism which may contribute to directional sensing and actin polymerization during chemotaxis; a mechanism which is conserved in mammalian neutrophils. In this review, we will discuss recent data on genes and pathways governing directional sensing and actin polymerization, with a particular emphasis on contributions from our laboratory.

Metastasis: recent discoveries and novel treatment strategies

Most cancer deaths are due to the development of metastases, hence the most important improvements in morbidity and mortality will result from prevention (or elimination) of such disseminated disease. Some would argue that treatments directed against metastasis are too late because cells have already escaped from the primary tumour. Such an assertion runs contrary to the significant but (for many common adult cancers) fairly modest improvements in survival following the use of adjuvant radiation and chemotherapy designed to eliminate disseminated cells after surgical removal of the primary tumour. Nonetheless, the debate raises important issues concerning the accurate early identification of clonogenic, metastatic cells, the discovery of novel, tractable targets for therapy, and the monitoring of minimal residual disease. We focus on recent findings regarding intrinsic and extrinsic molecular mechanisms controlling metastasis that determine how, when, and where cancers metastasise, and their implications for patient management in the 21st century.

The hyaluronan receptors CD44 and Rhamm (CD168) form complexes with ERK1,2 that sustain high basal motility in breast cancer cells

CD44 is an integral hyaluronan receptor that can promote or inhibit motogenic signaling in tumor cells. Rhamm is a nonintegral cell surface hyaluronan receptor (CD168) and intracellular protein that promotes cell motility in culture. Here we describe an autocrine mechanism utilizing cell surface Rhamm-CD44 interactions to sustain rapid basal motility in invasive breast cancer cell lines that requires endogenous hyaluronan synthesis and the formation of Rhamm-CD44-ERK1,2 complexes. Motile/invasive MDA-MB-231 and Ras-MCF10A cells produce more endogenous hyaluronan, cell surface CD44 and Rhamm, an oncogenic Rhamm isoform, and exhibit more elevated basal activation of ERK1,2 than less invasive MCF7 and MCF10A breast cancer cells. Furthermore, CD44, Rhamm, and ERK1,2 uniquely co-immunoprecipitate and co-localize in MDA-MB-231 and Ras-MCF10A cells. Combinations of anti-CD44, anti-Rhamm antibodies, and a MEK1 inhibitor (PD098059) had less-than-additive blocking effects, suggesting the action of all three proteins on a common motogenic signaling pathway. Collectively, these results show that cell surface Rhamm and CD44 act together in a hyaluronan-dependent autocrine mechanism to coordinate sustained signaling through ERK1,2, leading to high basal motility of invasive breast cancer cells. Therefore, an effect of CD44 on tumor cell motility may depend in part on its ability to partner with additional proteins, such as cell surface Rhamm.

The phosphoinositide 3-kinase signalling pathway as a therapeutic target in squamous cell carcinoma of the head and neck

Squamous cell carcinoma of the head and neck (SCCHN) is associated with high morbidity and mortality. Despite significant surgical advances and refinement in the delivery of chemotherapy and radiotherapy, prognosis has improved little in recent decades. Better local control has led to the late presentation of distant metastases and novel therapeutic agents are urgently required to prevent relapse, control disseminated disease and thus improve survival. PIK3CA encodes the p110alpha isoform of phosphoinositide 3-kinase (PI3-K) and is important in SCCHN, aberrations in its activity occurring early in the oncogenic process. PI3-K signalling promotes cell survival, proliferation, invasion and angiogenesis, all contributing to tumour progression. Activation of the PI3-K pathway may also mediate resistance to chemotherapy, radiotherapy and novel therapeutic agents such as epidermal growth factor receptor inhibitors. Elements of this signalling matrix, therefore, offer attractive therapeutic targets in SCCHN as inhibition of many malignant characteristics, as well as sensitisation to multiple treatment modalities, could be anticipated.

Ephrin-A1 facilitates mammary tumor metastasis through an angiogenesis-dependent mechanism mediated by EphA receptor and vascular endothelial growth factor in mice

Ephrin-A1, the prototypic ligand for EphA receptor tyrosine kinases, is overexpressed in vascularized tumors relative to normal tissue. Moreover, ephrin-A1-Fc fusion proteins induce endothelial cell sprouting, migration, and assembly in vitro, and s.c. vascular remodeling in vivo. Based on these data, we hypothesized that native, membrane-bound ephrin-A1 regulates tumor angiogenesis and progression. We tested this hypothesis using a transplantable mouse mammary tumor model. Small interfering RNA-mediated ephrin-A1 knockdown in metastatic mammary tumor cells significantly diminishes lung metastasis without affecting tumor volume, invasion, intravasation, or lung colonization upon i.v. injection in vivo. Ephrin-A1 knockdown reduced tumor-induced endothelial cell migration in vitro and microvascular density in vivo. Conversely, overexpression of ephrin-A1 in nonmetastatic mammary tumor cells elevated microvascular density and vascular recruitment. Overexpression of ephrin-A1 elevated wild-type but not EphA2-deficient endothelial cell migration toward tumor cells, suggesting that activation of EphA2 on endothelial cells is one mechanism by which ephrin-A1 regulates angiogenesis. Furthermore, ephrin-A1 knockdown diminished, whereas overexpression of ephrin-A1 elevated, vascular endothelial growth factor (VEGF) levels in tumor cell-conditioned medium, suggesting that ephrin-A1-mediated modulation of the VEGF pathway is another mechanism by which membrane-tethered ephrin-A1 regulates angiogenic responses from initially distant host endothelium. These data suggest that ephrin-A1 is a proangiogenic signal, regulating VEGF expression and facilitating angiogenesis-dependent metastatic spread.

Role of cytokines in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma is one of the most frequent cancers and standard treatment has only marginally improved the 5-year survival rate of patients with this disease in the last few decades. It is supposed that cytokine alterations in immune, inflammatory and angiogenetic regulatory routes within the head and neck squamous cell carcinoma microenvironment play a critical role in tumor aggressiveness, its response to chemo- and radiation therapies, as well as the development of immune escape mechanisms.