Nanoparticle mediated targeting of VEGFR and cancer stem cells for cancer therapy

Valsartan as a prophylactic treatment against breast cancer development and niche activation: What molecular sequels follow chronic AT-1R blockade?

AIMS

Transactivation of insulin-growth-factor-receptor (IGF-1R) by angiotensin-II-type-1-receptor (AT-1R) was only demonstrated in vascular-smooth-muscle cells and has never been tested in breast-cancer (BC). This investigation addressed the impact of chronic AT-1R blockade by valsartan (Val) on possible concurrent AT-1R/IGF-1R signaling inhibition, regressing BC-tumor-microenvironment (TME) cellular components activation, and hindering BC development.

MAIN METHODS

The effect of different Val doses (10, 20, 40 & 80 mg/kg/day for 490 days) was tested on dimethylbenz(a)anthracene (DMBA)-induced progesterone-promoted-BC in rats. The influence on intratumoral/circulating angiotensin-II (ANG-II) levels and AT-1R/Mas-R immunofluorescent-expression were assessed. The potential AT-1R/IGF-1R crosstalk within TME-BC-stem-cells (BCSCs) and cancer-associated-fibroblasts (CAFs) was evaluated by fluorescently marking these cells and locating the immunofluorescently-stained AT-1R/IGF-1R in them using confocal-laser-microscopy and further quantified by flow cytometry. In addition, the molecular alterations following blocking AT-1R were inspected including determining Src; crucial for IGF-1R transactivation by AT-1R, Notch-1; IGF-IR transcriptional-regulator, and PI3K/Akt &IL-6/STAT expression. Further, the suppression of CSCs' capabilities to maintain pluripotency, stemness features, epithelial-to-mesenchymal-transition (EMT), and angiogenesis was evaluated by assessing NANOG gene, aldehyde-dehydrogenase (ALDH), N-cadherin and vascular-endothelial-growth-factor (VEGF), respectively. Furthermore, the proliferative marker; Ki-67, was detected by immunostaining, and tumors were histologically graded using Elston-Ellis-modified-Scarff-Bloom-Richardson method.

KEY FINDINGS

Prophylactic Val significantly reduced tumor size, prolonged latency, reduced tumor histopathologic grade, decreased circulating/intratumoral-ANG-II levels, increased Mas-R, and decreased AT1R expression. AT-1R/IGF-1R were co-expressed with a high correlation coefficient on CAFs/BCSCs. Moreover, Val significantly attenuated IGF-1R transactivation and transcriptional regulation via Src and Notch-1 genes' downregulation and reduced Src/IGF-IR-associated PI3K/Akt and IL-6/STAT3 signaling. Further, Val significantly decreased intratumoral NANOG, ALDH, N-cadherin, VEGF, and Ki-67 levels.

SIGNIFICANCE

Chronic Val administration carries a potential for repurposing as adjuvant or conjunct therapy for patients at high risk for BC.

Development and testing of nanoparticles delivery for P7C3 small molecule using injury models

The use of nanoparticles (NPs) has emerged as a potential tool for safe and effective drug delivery. In the present study, we developed small molecule P7C3-based NPs and tested its efficacy and toxicity along with the tissue specific aptamer-modified P7C3 NPs. The P7C3 NPs were prepared using poly (D, L-lactic-co-glycolic acid) carboxylic acid (PLGA-COOH) polymer, were conjugated with skeletal muscle-specific RNA aptamer (A01B P7C3 NPs) and characterized for its cytotoxicity, cellular uptake, and wound healing in vitro. The A01B P7C3 NPs demonstrated an encapsulation efficiency of 30.2 ± 2.6%, with the particle size 255.9 ± 4.3 nm, polydispersity index of 0.335 ± 0.05 and zeta potential of + 10.4 ± 1.8mV. The FTIR spectrum of P7C3 NPs displayed complete encapsulation of the drug in the NPs. The P7C3 NPs and A01B P7C3 NPs displayed sustained drug release in vitro for up to 6 days and qPCR analysis confirmed A01B aptamer binding to P7C3 NPs. The C2C12 cells viability assay displayed no cytotoxic effects of all 3 formulations at 48 and 72 h. In addition, the cellular uptake of A01B P7C3 NPs in C2C12 myoblasts demonstrated higher uptake. In vitro assay mimicking wound healing showed improved wound closure with P7C3 NPs. In addition, P7C3 NPs significantly decreased TNF-α induced NF-κB activity in the C2C12/NF-κB reporter cells after 24-hour treatment. The P7C3 NPs showed 3-4-fold higher efficacy compared to P7C3 solutions in both wound-closure and inflammation assays in C2C12 cells. Furthermore, the P7C3 NPs showed 3-4-fold higher efficacy in reducing the infarct size and protected mouse hearts from ex vivo ischemia-reperfusion injury. Overall, this study demonstrates the safe and effective delivery of P7C3 NPs.

Recent Advances on Surface-Modified GBM Targeted Nanoparticles: Targeting Strategies and Surface Characterization

Glioblastoma multiforme (GBM) is the most common malignant brain tumor, associated with low long-term survival. Nanoparticles (NPs) developed against GBM are a promising strategy to improve current therapies, by enhancing the brain delivery of active molecules and reducing off-target effects. In particular, NPs hold high potential for the targeted delivery of chemotherapeutics both across the blood-brain barrier (BBB) and specifically to GBM cell receptors, pathways, or the tumor microenvironment (TME). In this review, the most recent strategies to deliver drugs to GBM are explored. The main focus is on how surface functionalizations are essential for BBB crossing and for tumor specific targeting. We give a critical analysis of the various ligand-based approaches that have been used to target specific cancer cell receptors and the TME, or to interfere with the signaling pathways of GBM. Despite the increasing application of NPs in the clinical setting, new methods for ligand and surface characterization are needed to optimize the synthesis, as well as to predict their in vivo behavior. An expert opinion is given on the future of this research and what is still missing to create and characterize a functional NP system for improved GBM targeting.

Polymeric nanoparticles—Promising carriers for cancer therapy

Polymeric nanoparticles (NPs) play an important role in controlled cancer drug delivery. Anticancer drugs can be conjugated or encapsulated by polymeric nanocarriers, which are known as polymeric nanomedicine. Polymeric nanomedicine has shown its potential in providing sustained release of drugs with reduced cytotoxicity and modified tumor retention, but until now, few delivery systems loading drugs have been able to meet clinical demands, so more efforts are needed. This research reviews the current state of the cancer drug-loading system by exhibiting a series of published articles that highlight the novelty and functions from a variety of different architectures including micelles, liposomes, dendrimers, polymersomes, hydrogels, and metal–organic frameworks. These may contribute to the development of useful polymeric NPs to achieve different therapeutic purposes.

Nanoparticle-based immunotherapy of pancreatic cancer

Pancreatic cancer (PC) has a complex and unique tumor microenvironment (TME). Due to the physical barrier formed by the desmoplastic stroma, the delivery of drugs to the tumor tissue is limited. The TME also contributes to resistance to various immunotherapies such as cancer vaccines, chimeric antigen receptor T cell therapy and immune checkpoint inhibitors. Overcoming and/or modulating the TME is therefore one of the greatest challenges in developing new therapeutic strategies for PC. Nanoparticles have been successfully used as drug carriers and delivery systems in cancer therapy. Recent experimental and engineering developments in nanotechnology have resulted in increased drug delivery and improved immunotherapy for PC. In this review we discuss and analyze the current nanoparticle-based immunotherapy approaches that are at the verge of clinical application. Particularly, we focus on nanoparticle-based delivery systems that improve the effectiveness of PC immunotherapy. We also highlight current clinical research that will help to develop new therapeutic strategies for PC and especially targeted immunotherapies based on immune checkpoint inhibitors.

The Integrated Study on the Chemical Profiling to Explore the Constituents and Mechanism of Traditional Chinese Medicine Preparation Huatuo Jiuxin Pills Based on UPLC-Q-TOF/MSE and Network Pharmacology

Huatuo Jiuxin Pills (HJP), a traditional Chinese medicine (TCM) preparation, has been widely used to treat Cardiovascular Diseases (CVDs) for more than 20 years. However, there were still gaps in the study of chemical components and potential pharmacological effects in the HJP. In this study, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MSE) combined with network pharmacology was used to comprehensively explore the chemical components in HJP and explore its potential active compounds and the mechanism for the treatment of CVDs. A total of 117 compounds, mainly including saponins, cholic acids, and bufadienolides, were rapidly identified and characterized. Simultaneously, the fragmentation mode and characteristic ion analysis of different types of representative compounds were carried out. Network pharmacology results showed that the more important active ingredients mainly include 5β‐hydroxybufotalin, 19 oxo‐cinobufagin, bufarenogin, etc. While, the main targets were PIK3CA, MAPK1, VEGFA and so on. Importantly, HJP has therapeutic effects on CVDs by acting on endocrine resistance, PI3K-Akt signaling pathway, HIF-1 signaling pathway, etc. In addition, molecular docking results showed that the core active ingredients with higher degrees in HJP have a strong affinity with the core targets of CVDs. The current work fills the gap in the chemical substance basis of HJP, and also facilitates a better understanding of the effective components, therapeutic targets, and signaling pathways of HJP in the treatment of CVDs.

Photodynamic Therapy and Hyperthermia in Combination Treatment-Neglected Forces in the Fight against Cancer

Cancer is one of the leading causes of death in humans. Despite the progress in cancer treatment, and an increase in the effectiveness of diagnostic methods, cancer is still highly lethal and very difficult to treat in many cases. Combination therapy, in the context of cancer treatment, seems to be a promising option that may allow minimizing treatment side effects and may have a significant impact on the cure. It may also increase the effectiveness of anti-cancer therapies. Moreover, combination treatment can significantly increase delivery of drugs to cancerous tissues. Photodynamic therapy and hyperthermia seem to be ideal examples that prove the effectiveness of combination therapy. These two kinds of therapy can kill cancer cells through different mechanisms and activate various signaling pathways. Both PDT and hyperthermia play significant roles in the perfusion of a tumor and the network of blood vessels wrapped around it. The main goal of combination therapy is to combine separate mechanisms of action that will make cancer cells more sensitive to a given therapeutic agent. Such an approach in treatment may contribute toward increasing its effectiveness, optimizing the cancer treatment process in the future.

Molecular targets for the management of gastrointestinal cancer using melatonin, a natural endogenous body hormone

Gastrointestinal cancer is one of the most common cancers globally. Melatonin, a natural endogenous body hormone, has been of interest for years, due to its anti-cancer characteristics, such as antiproliferative, antimetastatic, and cytotoxic as well as apoptotic induction. Through regulating several proteins such as melatonin upregulated mRNAs and proteins of downregulated Bcl-2-associated X protein (Bax), and B-cell lymphoma 2 (Bcl-2), as well as cytoplasmic protein such as calcium-binding proteins calmodulin or tubulin, and nuclear receptors, including RORα/RZR, and acts by non-receptor-regulated mechanisms, melatonin can exert anti-cancer efficacy. Moreover, melatonin modulates angiogenesis by targeting mRNA and protein expression of endothelin-converting enzyme (ECE-1) protein. In the present review, we address in vivo, in vitro and clinical reports on its anti-cancer efficacies, and the molecular mechanisms of action responsible for these effects. We advance the possibility of therapeutic melatonin administration for cancer therapy.

The role of melatonin in colorectal cancer treatment: a comprehensive review

Colorectal cancer (CRC) is one of the most common types of cancer worldwide, known as the second leading cause of cancer-related deaths annually. Currently, multimodal treatment strategies, including surgical resection, combined with chemotherapy and radiotherapy, have been used as conventional treatments in patients with CRC. However, clinical outcome of advanced stage disease remains relatively discouraging, due mainly to appearance of CRC chemoresistance, toxicity, and other detrimental side effects. New strategies to overcome these limitations are essential. During the last decades, melatonin (MLT) has been shown to be a potent antiproliferative, anti-metastatic agent with cytotoxic effects on different types of human malignancies, including CRC. Hence, this comprehensive review compiles the available experimental and clinical data analyzing the effects of MLT treatment in CRC patients and its underlying molecular mechanisms.

Cancer Stem Cells and Combination Therapies to Eradicate Them

Cancer stem cells (CSCs) show self-renewal ability and multipotential differentiation, like normal stem or progenitor cells, and which proliferate uncontrollably and can escape the effects of drugs and phagocytosis by immune cells. Traditional monotherapies, such as surgical resection, radiotherapy and chemotherapy, cannot eradicate CSCs, however, combination therapy may be more effective at eliminating CSCs. The present review summarizes the characteristics of CSCs and several promising combination therapies to eradicate them.

Hypoxia-responsive nanoparticle based drug delivery systems in cancer therapy: An up-to-date review

Hypoxia is a salient feature observed in most solid malignancies that holds a pivotal role in angiogenesis, metastasis and resistance to conventional cancer therapeutic approaches, and thus enables cancer progression. However, the typical characteristics of hypoxic cells such as low oxygen levels and highly bio-reductive environment can offer stimuli-responsive drug release to aid in tumor-specific chemo, radio, photodyanamic and sonodynamic therapies. This approach based on targeting the poorly oxygenated tumor habitats offers the prospective to overcome the difficulties that arises due to heterogenic nature of tumor and could be possibly used in the design of diagnostic as well as therapeutic nanocarriers for targeting various types of solid cancers. Consequently, hypoxia triggered nanoparticle based drug delivery systems is a rapidly progressing research area in developing effective strategies to combat drug-resistance in solid tumors. The present review presents the recent advances in the development of hypoxia-responsive nanovehicles for drug delivery to heterogeneous tumors. The initial sections of the article provides insights into the development of hypoxia in growing cancer and its role in disease progression. The current limitations and the future prospective of hypoxia-stimulated nanomachines for cancer treatment are also discussed.

An in vitro Assessment of Thermo-Reversible Gel Formulation Containing Sunitinib Nanoparticles for Neovascular Age-Related Macular Degeneration

Anti-vascular endothelial growth factor agents have been widely used to treat several eye diseases including age-related macular degeneration (AMD). An approach to maximize the local concentration of drug at the target site and minimize systemic exposure is to be sought. Sunitinib malate, a multiple receptor tyrosine kinase inhibitor was encapsulated in poly(lactic-co-glycolic acid) nanoparticles to impart sustained release. The residence time in vitreal fluid was further increased by incorporating nanoparticles in thermo-reversible gel. Nanoparticles were characterized using TEM, DSC, FTIR, and in vitro drug release profile. The cytotoxicity of the formulation was assessed on ARPE-19 cells using the MTT assay. The cellular uptake, wound scratch assay, and VEGF expression levels were determined in in vitro settings. The optimized formulation had a particle size of 164.5 nm and zeta potential of - 18.27 mV. The entrapment efficiency of 72.0% ± 3.5% and percent drug loading of 9.1 ± 0.7% were achieved. The viability of ARPE-19 cells was greater than 90% for gel loaded, as such and blank nanoparticles at 10 μM and 20 μM concentration tested, whereas for drug solution viability was found to be 83% and 71% respectively at above concentration. The cell viability results suggest the compatibility of the developed formulation. Evaluation of cellular uptake, wound scratch assay, and VEGF expression levels for the developed formulations indicated that the formulation had higher uptake, superior anti-angiogenic potential, and prolonged inhibition of VEGF activity compared with drug solution. The results showed successful development of sunitinib-loaded nanoparticle-based thermo-reversible gel which may be used for the treatment of neovascular AMD.

Emerging functional markers for cancer stem cell-based therapies: Understanding signaling networks for targeting metastasis

Metastasis is one of the most challenging issues in cancer patient management, and effective therapies to specifically target disease progression are missing, emphasizing the urgent need for developing novel anti-metastatic therapeutics. Cancer stem cells (CSCs) gained fast attention as a minor population of highly malignant cells within liquid and solid tumors that are responsible for tumor onset, self-renewal, resistance to radio- and chemotherapies, and evasion of immune surveillance accelerating recurrence and metastasis. Recent progress in the identification of their phenotypic and molecular characteristics and interactions with the tumor microenvironment provides great potential for the development of CSC-based targeted therapies and radical improvement in metastasis prevention and cancer patient prognosis. Here, we report on newly uncovered signaling mechanisms controlling CSC's aggressiveness and treatment resistance, and CSC-specific agents and molecular therapeutics, some of which are currently under investigation in clinical trials, gearing towards decisive functional CSC intrinsic or surface markers. One special research focus rests upon subverted regulatory pathways such as insulin-like growth factor 1 receptor signaling and its interactors in metastasis-initiating cell populations directly related to the gain of stem cell- and EMT-associated properties, as well as key components of the E2F transcription factor network regulating metastatic progression, microenvironmental changes, and chemoresistance. In addition, the study provides insight into systems biology tools to establish complex molecular relationships behind the emergence of aggressive phenotypes from high-throughput data that rely on network-based analysis and their use to investigate immune escape mechanisms or predict clinical outcome-relevant CSC receptor signaling signatures. We further propose that customized vector technologies could drastically enhance systemic drug delivery to target sites, and summarize recent progress and remaining challenges. This review integrates available knowledge on CSC biology, computational modeling approaches, molecular targeting strategies, and delivery techniques to envision future clinical therapies designed to conquer metastasis-initiating cells.

Cancer stem cells (CSCs), cervical CSCs and targeted therapies

Accumulating evidence has shown that cancer stem cells (CSCs) have a tumour-initiating capacity and play crucial roles in tumour metastasis, relapse and chemo/radio-resistance. As tumour propagation initiators, CSCs are considered to be promising targets for obtaining a better therapeutic outcome. Cervical carcinoma is the most common gynaecological malignancy and has a high cancer mortality rate among females. As a result, the investigation of cervical cancer stem cells (CCSCs) is of great value. However, the numbers of cancer cells and corresponding CSCs in malignancy are dynamically balanced, and CSCs may reside in the CSC niche, about which little is known to date. Therefore, due to their complicated molecular phenotypes and biological behaviours, it remains challenging to obtain “purified” CSCs and continuously culture CSCs for further in vitro studies without the cells losing their stem properties. At present, CSC-related markers and functional assays are used to purify, identify and therapeutically target CSCs both in vitro and in vivo. Nevertheless, CSC-related markers are not universal to all tumour types, although some markers may be valid in multiple tumour types. Additionally, functional identifications based on CSC-specific properties are usually limited in in vivo studies. Furthermore, an optimal method for identifying potential CCSCs in CCSC studies has not been previously published, and these techniques are currently of great importance. This article updates our knowledge on CSCs and CCSCs, reviews potential stem cell markers and functional assays for identifying CCSCs, and describes the potential of targeting CCSCs in the treatment of cervical carcinoma.

Advances in cancer stem cell targeting: How to strike the evil at its root

Cancer progression to metastatic stages is still unmanageable and the promise of effective anti-metastatic therapy remains largely unmet, emphasizing the need to develop novel therapeutics. The special focus here is on cancer stem cells (CSC) as the seed of tumor initiation, epithelial-mesenchymal transition, chemoresistance and, as a consequence, drivers of metastatic dissemination. We report on targeted therapies gearing towards the CSC's internal and membrane-anchored markers using agents such as antibody derivatives, nucleic therapeutics, small molecules and genetic payloads. Another emphasis lies on novel proceedings envisaged to deliver current and prospective therapies to the target sites using newest viral and non-viral vector technologies. In this review, we summarize recent progress and remaining challenges in therapeutic strategies to combat CSC.

Exploring the Potential of Nanotherapeutics in Targeting Tumor Microenvironment for Cancer Therapy

Advanced research in the field of cancer biology clearly demonstrated the key role of tumor microenvironment (TME) in cancer development and metastasis particularly in solid tumors. Components of TME, being non-neoplastic in nature provide supportive and permissive conditions for the growth of cancer cells. Hence it is important to modify TME in cancer therapy and this would be achieved by better understanding of TME morphological features and functioning of stromal components. Nanotechnology based drug delivery offers various advantages such as prolonged circulation time, delivery of cargo at desired site, improved bioavailability, reduced toxicity etc. over conventional chemotherapeutics. Abnormal characteristic features of TME play a paradoxical role in nanoparticulate drug delivery. Leaky vasculature, acidic and hypoxic conditions of TME helps in the accumulation of tailored nanoparticles whereas high interstitial pressure and dense stroma restrict the extravasation, homogenous distribution of nanocarriers in TME. This review mainly discusses the potential of nanotherapeutics in targeting TME by briefly discussing stromal components, therapeutic opportunities and barriers offered by TME for nanoparticulate drug delivery. Updated information on TME remodeling strategies for improved drug delivery and specific targeting of individual stromal components are also outlined.

Gamabufotalin, a major derivative of bufadienolide, inhibits VEGF-induced angiogenesis by suppressing VEGFR-2 signaling pathway

Gamabufotalin (CS-6), a main active compound isolated from Chinese medicine Chansu, has been shown to strongly inhibit cancer cell growth and inflammatory response. However, its effects on angiogenesis have not been known yet. Here, we sought to determine the biological effects of CS-6 on signaling mechanisms during angiogenesis. Our present results fully demonstrate that CS-6 could significantly inhibit VEGF triggered HUVECs proliferation, migration, invasion and tubulogenesis in vitro and blocked vascularization in Matrigel plugs impregnated in C57/BL6 mice as well as reduced vessel density in human lung tumor xenograft implanted in nude mice. Computer simulations revealed that CS-6 interacted with the ATP-binding sites of VEGFR-2 using molecular docking. Furthermore, western blot analysis indicated that CS-6 inhibited VEGF-induced phosphorylation of VEGFR-2 kinase and suppressed the activity of VEGFR-2-mediated signaling cascades. Therefore, our studies demonstrated that CS-6 inhibited angiogenesis by inhibiting the activation of VEGFR-2 signaling pathways and CS-6 could be a potential candidate in angiogenesis-related disease therapy.

Microenvironment-Responsive Three-Pronged Approach Breaking Traditional Chemotherapy to Target Cancer Stem Cells for Synergistic Inoperable Large Tumor Therapy

Three-pronged nanoparticles (NPs) that can efficiently prohibit the proliferation of large tumor are developed for inoperable large tumor therapy. The NPs achieve spatially and temporally controlled release of drugs in target sites. The NPs induce the apoptosis of differentiated cancer cells, cancer stem cells, and vascular niches simultaneously. Importantly, the three-pronged NPs inhibit the growth of large tumors without recurrence.

The Extraordinary Progress in Very Early Cancer Diagnosis and Personalized Therapy: The Role of Oncomarkers and Nanotechnology

The impact of nanotechnology on oncology is revolutionizing cancer diagnosis and therapy and largely improving prognosis. This is mainly due to clinical translation of the most recent findings in cancer research, that is, the application of bio- and nanotechnologies. Cancer genomics and early diagnostics are increasingly playing a key role in developing more precise targeted therapies for most human tumors. In the last decade, accumulation of basic knowledge has resulted in a tremendous breakthrough in this field. Nanooncology, through the discovery of new genetic and epigenetic biomarkers, has facilitated the development of more sensitive biosensors for early cancer detection and cutting-edge multifunctionalized nanoparticles for tumor imaging and targeting. In the near future, nanooncology is expected to enable a very early tumor diagnosis, combined with personalized therapeutic approaches.

Hypoxia-responsive drug–drug conjugated nanoparticles for breast cancer synergistic therapy

(A) Chemical structure of IR–AZO–CA4 molecule and preparation of IR–AZO–CA4/CP NPs. (B) Schematic illustration of the hypoxia-responsive drug–drug conjugated NPs in hypoxic cells and normoxic cells.

Cell-specific optoporation with near-infrared ultrafast laser and functionalized gold nanoparticles

Selective targeting of diseased cells can increase therapeutic efficacy and limit off-target adverse effects. We developed a new tool to selectively perforate living cells with functionalized gold nanoparticles (AuNPs) and near-infrared (NIR) femtosecond (fs) laser. The receptor CD44 strongly expressed by cancer stem cells was used as a model for selective targeting. Citrate-capped AuNPs (100 nm in diameter) functionalized with 0.01 orthopyridyl-disulfide-poly(ethylene glycol) (5 kDa)-N-hydroxysuccinimide (OPSS-PEG-NHS) conjugated to monoclonal antibodies per nm(2) and 5 μM HS-PEG (5 kDa) were colloidally stable in cell culture medium containing serum proteins. These AuNPs attached mostly as single particles 115 times more to targeted CD44(+) MDA-MB-231 and CD44(+) ARPE-19 cells than to non-targeted CD44(-) 661W cells. Optimally functionalized AuNPs enhanced the fs laser (800 nm, 80-100 mJ cm(-2) at 250 Hz or 60-80 mJ cm(-2) at 500 Hz) to selectively perforate targeted cells without affecting surrounding non-targeted cells in co-culture. This novel highly versatile treatment paradigm can be adapted to target and perforate other cell populations by adapting to desired biomarkers. Since living biological tissues absorb energy very weakly in the NIR range, the developed non-invasive tool may provide a safe, cost-effective clinically relevant approach to ablate pathologically deregulated cells and limit complications associated with surgical interventions.

Chemistry for oncotheranostic gold nanoparticles

This review presents in a comprehensive ways the chemical methods used to functionalize gold nanoparticles with focus on anti-cancer applications. The review covers the parameters required for the synthesis gold nanoparticles with defined shapes and sizes, method for targeted delivery in tumours, and selected examples of anti-cancers compounds delivered with gold nanoparticles. A short survey of bioassays for oncology based on gold nanoparticles is also presented.

Wide-field hyperspectral 3D imaging of functionalized gold nanoparticles targeting cancer cells by reflected light microscopy

We present a new hyperspectral reflected light microscopy system with a scanned broadband supercontinuum light source. This wide-field and low phototoxic hyperspectral imaging system has been successful for performing spectral three-dimensional (3D) localization and spectroscopic identification of CD44-targeted PEGylated AuNPs in fixed cell preparations. Such spatial and spectral information is essential for the improvement of nanoplasmonic-based imaging, disease detection and treatment in complex biological environment. The presented system can be used for real-time 3D NP tracking as spectral sensors, thus providing new avenues in the spatio-temporal characterization and detection of bioanalytes. 3D image of the distribution of functionalized AuNPs attached to CD44-expressing MDA-MB-231 human cancer cells.

Synergistic effect of angiotensin II on vascular endothelial growth factor-A-mediated differentiation of bone marrow-derived mesenchymal stem cells into endothelial cells

INTRODUCTION

Increased levels of angiotensin II (Ang II) and activity of Ang II receptor type 1 (AT1R) elicit detrimental effects in cardiovascular disease. However, the role of Ang II receptor type 2 (AT2R) remains poorly defined. Mesenchymal stem cells (MSCs) replenish and repair endothelial cells in the cardiovascular system. Herein, we investigated a novel role of angiotensin signaling in enhancing vascular endothelial growth factor (VEGF)-A-mediated differentiation of MSCs into endothelial cells (ECs).

METHODS

Bone marrow was aspirated from the femurs of Yucatan microswine. MSCs were extracted via ficoll density centrifugation technique and were strongly immunopositive for MSC markers, CD44, CD90, and CD105, but negative for hematopoietic markers, CD14 and CD45. Subsequently, naïve MSCs were differentiated for 10 days in varying concentrations and combinations of VEGF-A, Ang II, and AT1R or AT2R antagonists. Markers specific to ECs were determined by FACS analysis.

RESULTS

AT1R and AT2R expression and cellular localization was demonstrated in MSCs stimulated with VEGF-A and Ang II via quantitative RT-PCR and immunofluorescence, respectively. Differentiation of naïve MSCs in media containing Ang II (2 ng/ml) plus low-dose VEGF-A (2 ng/ml) produced a significantly higher percentage of cells that were positive for expression of EC markers (for example, platelet endothelial cell adhesion molecule, vascular endothelial Cadherin and von Willebrand factor) compared to VEGF-A alone. Ang II alone failed to induce EC marker expression. MSCs differentiated with the combination of Ang II and VEGF-A were capable of forming capillary tubes using an in vitro angiogenesis assay. Induction of EC marker expression was greatly attenuated by co-treatment of Ang II/VEGF-A with the AT2R antagonist PD123319, but not the AT1R antagonist telmisartan.

CONCLUSIONS

We report the presence of functional AT2R receptor on porcine bone marrow-derived MSCs, where it positively regulates EC differentiation. These findings have significant implications toward therapeutic approaches based on activation of AT2R, which could be a means to stimulate regeneration of damaged endothelium and prevent vascular thrombosis.

Hyperspectral darkfield microscopy of PEGylated gold nanoparticles targeting CD44-expressing cancer cells

We present a new hyperspectral darkfield imaging system with a scanned broadband supercontinuum light source. We observed the specific attachment of the functionalized gold plasmonic nanoparticles (AuNPs) targeting CD44(+) human breast cancer cells by conventional and by proposed hyperspectral darkfield microscopy. This wide-field and low phototoxic hyperspectral imaging system has been successful for performing spectral three-dimensional (3D) localization and spectroscopic identification of CD44-targeted PEGylated AuNPs in fixed cell preparations. Such spatial and spectral information is essential for the improvement of nanoplasmonic-based imaging, disease detection and treatment in complex biological environment. Presented system capability for 3D NP tracking will also enable investigation of specific sub-cellular activity with the use of NPs as spectral sensors.

[FUNCTIONAL ACTIVITY OF EHRLICH CARCINOMA CELLS AFTER TREATMENT WITH HYBRID NANOCOMPLEXES CONTAINING ORTHOVANADATES OF RARE-EARTH ELEMENTS, CHOLESTEROL AND LUMINESCENT DYE]

Tumor development is the consequence of expanding the population of low differentiated cells with unlimited self-maintenance potential, i.e. cancer stem cells (CSCs). Application of new forms of nanocomposites capable of binding to CSCs and inducing the tumor destruction is perspective direction for treating this pathology. There have been developed the methods of obtaining hybrid nanocomplexes containing rare-earth orthovanadates GdYVO4:Eu³⁺, cholesterol and luminescent dye Dil. By immune fluorescence method using monoclonal antibodies to CD44, CD24, CD117 and Sca-1 markers there has been established the change in the ratio of tumor progenitors of various differentiation levels in a general pool of Ehrlich carcinoma (EC) after treatment with hybrid nanocomplexes. Essential reduction in the concentration of the most tumorogenic CD44high cells with simultaneous rise in the number of CD117⁺-cells resulted in an increased index of CD44high/CD117⁺ ratio. It has been demonstrated that application of hybrid nanocomplexes suppressed the tumor growth almost by 80%. The value of cooperative interactions of the cells with different phenotype signs in tumor sites has been proved. The index of CD44high/CD117⁺ ratio can be used as one of diagnostic and prognostic parameters of development and inactivation rate of tumor process when using different types of anti-tumor therapy.

Effect of melatonin on tumor growth and angiogenesis in xenograft model of breast cancer

As neovascularization is essential for tumor growth and metastasis, controlling angiogenesis is a promising tactic in limiting cancer progression. Melatonin has been studied for their inhibitory properties on angiogenesis in cancer. We performed an in vivo study to evaluate the effects of melatonin treatment on angiogenesis in breast cancer. Cell viability was measured by MTT assay after melatonin treatment in triple-negative breast cancer cells (MDA-MB-231). After, cells were implanted in athymic nude mice and treated with melatonin or vehicle daily, administered intraperitoneally 1 hour before turning the room light off. Volume of the tumors was measured weekly with a digital caliper and at the end of treatments animals underwent single photon emission computed tomography (SPECT) with Technetium-99m tagged vascular endothelial growth factor (VEGF) C to detect in vivo angiogenesis. In addition, expression of pro-angiogenic/growth factors in the tumor extracts was evaluated by membrane antibody array and collected tumor tissues were analyzed with histochemical staining. Melatonin in vitro treatment (1 mM) decreased cell viability (p<0.05). The breast cancer xenografts nude mice treated with melatonin showed reduced tumor size and cell proliferation (Ki-67) compared to control animals after 21 days of treatment (p<0.05). Expression of VEGF receptor 2 decreased significantly in the treated animals compared to that of control when determined by immunohistochemistry (p<0.05) but the changes were not significant on SPECT (p>0.05) images. In addition, there was a decrease of micro-vessel density (Von Willebrand Factor) in melatonin treated mice (p<0.05). However, semiquantitative densitometry analysis of membrane array indicated increased expression of epidermal growth factor receptor and insulin-like growth factor 1 in treated tumors compared to vehicle treated tumors (p<0.05). In conclusion, melatonin treatment showed effectiveness in reducing tumor growth and cell proliferation, as well as in the inhibition of angiogenesis.

Paclitaxel-incorporated nanoparticles using block copolymers composed of poly(ethylene glycol)/poly(3-hydroxyoctanoate)

Block copolymers composed of poly(3-hydroxyoctanoate) (PHO) and methoxy poly(ethylene glycol) (PEG) were synthesized to prepare paclitaxel-incorporated nanoparticle for antitumor drug delivery. In a (1)H-NMR study, chemical structures of PHO/PEG block copolymers were confirmed and their molecular weight (M.W.) was analyzed with gel permeation chromatography (GPC). Paclitaxel as a model anticancer drug was incorporated into the nanoparticles of PHO/PEG block copolymer. They have spherical shapes and their particle sizes were less than 100 nm. In a (1)H-NMR study in D2O, specific peaks of PEG solely appeared while peaks of PHO disappeared, indicating that nanoparticles have core-shell structures. The higher M.W. of PEG decreased loading efficiency and particle size. The higher drug feeding increased drug contents and average size of nanoparticles. In the drug release study, the higher M.W. of PEG block induced the acceleration of drug release rate. The increase in drug contents induced the slow release rate of drug. In an antitumor activity study in vitro, paclitaxel nanoparticles have practically similar anti-proliferation activity against HCT116 human colon carcinoma cells. In an in vivo animal study using HCT116 colon carcinoma cell-bearing mice, paclitaxel nanoparticles have enhanced antitumor activity compared to paclitaxel itself. Therefore, paclitaxel-incorporated nanoparticles of PHO/PEG block copolymer are a promising vehicle for antitumor drug delivery.

Nanopreparations to overcome multidrug resistance in cancer

Multidrug resistance is the most widely exploited phenomenon by which cancer eludes chemotherapy. Broad variety of factors, ranging from the cellular ones, such as over-expression of efflux transporters, defective apoptotic machineries, and altered molecular targets, to the physiological factors such as higher interstitial fluid pressure, low extracellular pH, and formation of irregular tumor vasculature are responsible for multidrug resistance. A combination of various undesirable factors associated with biological surroundings together with poor solubility and instability of many potential therapeutic small & large molecules within the biological systems and systemic toxicity of chemotherapeutic agents has necessitated the need for nano-preparations to optimize drug delivery. The physiology of solid tumors presents numerous challenges for successful therapy. However, it also offers unique opportunities for the use of nanotechnology. Nanoparticles, up to 400 nm in size, have shown great promise for carrying, protecting and delivering potential therapeutic molecules with diverse physiological properties. In this review, various factors responsible for the MDR and the use of nanotechnology to overcome the MDR, the use of spheroid culture as well as the current technique of producing microtumor tissues in vitro are discussed in detail.

Drug-loaded nanoparticle systems and adult stem cells: a potential marriage for the treatment of malignant glioma?

Despite all recent advances in malignant glioma research, only modest progress has been achieved in improving patient prognosis and quality of life. Such a clinical scenario underscores the importance of investing in new therapeutic approaches that, when combined with conventional therapies, are able to effectively eradicate glioma infiltration and target distant tumor foci. Nanoparticle-loaded delivery systems have recently arisen as an exciting alternative to improve targeted anti-glioma drug delivery. As drug carriers, they are able to efficiently protect the therapeutic agent and allow for sustained drug release. In addition, their surface can be easily manipulated with the addition of special ligands, which are responsible for enhancing tumor-specific nanoparticle permeability. However, their inefficient intratumoral distribution and failure to target disseminated tumor burden still pose a big challenge for their implementation as a therapeutic option in the clinical setting. Stem cell-based delivery of drug-loaded nanoparticles offers an interesting option to overcome such issues. Their ability to incorporate nanoparticles and migrate throughout interstitial barriers, together with their inherent tumor-tropic properties and synergistic anti-tumor effects make these stem cell carriers a good fit for such combined therapy. In this review, we will describe the main nanoparticle delivery systems that are presently available in preclinical and clinical studies. We will discuss their mechanisms of targeting, current delivery methods, attractive features and pitfalls. We will also debate the potential applications of stem cell carriers loaded with therapeutic nanoparticles in anticancer therapy and why such an attractive combined approach has not yet reached clinical trials.

MMP-9 increases HER2/neu expression and alters apoptosis levels in human mammary epithelial cells (HMEC)

HER2/neu overexpression leads to poorer prognosis and higher risk of disease reoccurrence in breast cancer patients. The causative factors responsible for increasing HER2/neu expression levels on mammary cells are not known. We investigated whether factors associated with inflammation or metastasis could induce HER2/neu expression on human mammary epithelial cells (HMECs). Human mammary epithelial cells and several human breast cancer cell lines used in our studies were treated with several agents, including estrogen and matrix metalloproteinase-9 (MMP-9), either alone or in various combinations. Relative expression of HER2/neu on the surface of target cells was assessed using fluorochrome-tagged antibodies and a fluorescence cytometer. HER2/neu gene expression was also determined by Western blot analysis and PCR. Apoptosis levels were also determined. MMP-9, administered either alone or in combination with interleukin-7 and estrogen, caused a significant rise in HER2/neu expression on the surface of HMECs. The induction in HER2/neu protein expression was suppressed using a MMP-9 inhibitor. Similar results were obtained for breast cancer cells treated with the estrogen in combination with MMP-9. MMP-9 treatment significantly decreased apoptotic levels in HMECs. Our results indicate that MMP-9 is a regulator of HER2/neu expression on human mammary epithelial cells and suggest that upregulation of HER2/neu by MMP-9 may be relevant to altering the characteristics of normal mammary cells toward a transformed phenotype.

CD44+/CD24- breast cancer cells isolated from MCF-7 cultures exhibit enhanced angiogenic properties

BACKGROUND

Recent studies suggest that the relationship between cancer stem cells (CSCs) and the vascular niche may be bidirectional; the niche can support the growth and renewal of CSCs, and CSCs may contribute to the maintenance of the niche. There is little knowledge concerning the role of breast cancer stem cells in promoting tumor angiogenesis.

AIM

For human breast cancers, CSCs have been shown to be associated with a CD44+/CD24- phenotype. We investigated the potential activities of CD44+/CD24- breast cancer stem cells in promoting tumor angiogenesis.

METHODS

The expression of pro-angiogenic genes was determined by quantitative real-time RT-PCR. Endothelial cell migration assays were employed to evaluate effects of conditioned media from CD44+/CD24- on human umbilical vein endothelial cells. A chorioallantoic membrane (CAM) assay was used to study the potential of CD44+/CD24- cells to promote angiogenesis.

RESULTS

In our study, CD44+/CD24- cells expressed elevated levels of pro-angiogenic factors compared with CD44+/CD24+ cells. CD44+/CD24- cell-conditioned media significantly increased endothelial cell migration. Breast cancer cell lines enriched with CD44+/CD24- cells were more pro-angiogenic in the CAM assay than those lacking a CD44+/CD24- subpopulation. CD44+/CD24- cells sorted from MCF-7 cell lines were more pro-angiogenic in a CAM assay than CD44+/CD24+ cells. Furthermore, the VEGF concentration was significantly higher in CD44+/CD24- cell-conditioned media than in CD44+/CD24+ cell-conditioned media. The pro-angiogenic effect of CD44+/CD24- cells on endothelial cells was abolished by bevacizumab.

CONCLUSION

Our findings demonstrate that CD44+/CD24- breast cancer stem cells have substantial pro-angiogenic potential and activity. This provides new insights to explore in the development of targeted therapies.