From Ugly Duckling to Swan: Unexpected Identification from Cell-SELEX of an Anti-Annexin A2 Aptamer Targeting Tumors

Background

Cell-SELEX is now widely used for the selection of aptamers against cell surface biomarkers. However, despite negative selection steps using mock cells, this method sometimes results in aptamers against undesirable targets that are expressed both on mock and targeted cells. Studying these junk aptamers might be useful for further applications than those originally envisaged.

Methodology/Principal Findings

Cell-SELEX was performed to identify aptamers against CHO-K1 cells expressing human Endothelin type B receptor (ET_BR). CHO-K1 cells were used for negative selection of aptamers. Several aptamers were identified but no one could discriminate between both cell lines. We decided to study one of these aptamers, named ACE4, and we identified that it binds to the Annexin A2, a protein overexpressed in many cancers. Radioactive binding assays and flow cytometry demonstrated that the aptamer was able to bind several cancer cell lines from different origins, particularly the MCF-7 cells. Fluorescence microscopy revealed it could be completely internalized in cells in 2 hours. Finally, the tumor targeting of the aptamer was evaluated in vivo in nude mice xenograft with MCF-7 cells using fluorescence diffuse optical tomography (fDOT) imaging. Three hours after intravenous injection, the aptamer demonstrated a significantly higher uptake in the tumor compared to a scramble sequence.

Conclusions/Significance

Although aptamers could be selected during cell-SELEX against other targets than those initially intended, they represent a potential source of ligands for basic research, diagnoses and therapy. Here, studying such aptamers, we identify one with high affinity for Annexin A2 that could be a promising tool for biomedical application.     

FeCo/graphite nanocrystals for multi-modality imaging of experimental vascular inflammation

Background

FeCo/graphitic-carbon nanocrystals (FeCo/GC) are biocompatible, high-relaxivity, multi-functional nanoparticles. Macrophages represent important cellular imaging targets for assessing vascular inflammation. We evaluated FeCo/GC for vascular macrophage uptake and imaging in vivo using fluorescence and MRI.

Methods and Results

Hyperlipidemic and diabetic mice underwent carotid ligation to produce a macrophage-rich vascular lesion. In situ and ex vivo fluorescence imaging were performed at 48 hours after intravenous injection of FeCo/GC conjugated to Cy5.5 (n = 8, 8 nmol of Cy5.5/mouse). Significant fluorescence signal from FeCo/GC-Cy5.5 was present in the ligated left carotid arteries, but not in the control (non-ligated) right carotid arteries or sham-operated carotid arteries (p = 0.03 for ligated vs. non-ligated). Serial in vivo 3T MRI was performed at 48 and 72 hours after intravenous FeCo/GC (n = 6, 270 µg Fe/mouse). Significant T2* signal loss from FeCo/GC was seen in ligated left carotid arteries, not in non-ligated controls (p = 0.03). Immunofluorescence staining showed colocalization of FeCo/GC and macrophages in ligated carotid arteries.

Conclusions

FeCo/GC accumulates in vascular macrophages in vivo, allowing fluorescence and MR imaging. This multi-functional high-relaxivity nanoparticle platform provides a promising approach for cellular imaging of vascular inflammation.     

Development of an Efficient Targeted Cell-SELEX Procedure for DNA Aptamer Reagents

Background

DNA aptamers generated by cell-SELEX offer an attractive alternative to antibodies, but generating aptamers to specific, known membrane protein targets has proven challenging, and has severely limited the use of aptamers as affinity reagents for cell identification and purification.

Methodology

We modified the BJAB lymphoblastoma cell line to over-express the murine c-kit cell surface receptor. After six rounds of cell-SELEX, high-throughput sequencing and bioinformatics analysis, we identified aptamers that bound BJAB cells expressing c-kit but not wild-type BJAB controls. One of these aptamers also recognizes c-kit endogenously expressed by a mast cell line or hematopoietic progenitor cells, and specifically blocks binding of the c-kit ligand stem cell factor (SCF). This aptamer enables better separation by fluorescence-activated cell sorting (FACS) of c-kit⁺ hematopoietic progenitor cells from mixed bone marrow populations than a commercially available antibody, suggesting that this approach may be broadly useful for rapid isolation of affinity reagents suitable for purification of other specific cell types.

Conclusions/Significance

Here we describe a novel procedure for the efficient generation of DNA aptamers that bind to specific cell membrane proteins and can be used as high affinity reagents. We have named the procedure STACS (Specific TArget Cell-SELEX).     

Selection of DNA Aptamers against Glioblastoma Cells with High Affinity and Specificity

Background

Glioblastoma is the most common and most lethal form of brain tumor in human. Unfortunately, there is still no effective therapy to this fatal disease and the median survival is generally less than one year from the time of diagnosis. Discovery of ligands that can bind specifically to this type of tumor cells will be of great significance to develop early molecular imaging, targeted delivery and guided surgery methods to battle this type of brain tumor.

Methodology/Principal Findings

We discovered two target-specific aptamers named GBM128 and GBM131 against cultured human glioblastoma cell line U118-MG after 30 rounds selection by a method called cell-based Systematic Evolution of Ligands by EXponential enrichment (cell-SELEX). These two aptamers have high affinity and specificity against target glioblastoma cells. They neither recognize normal astraglial cells, nor do they recognize other normal and cancer cell lines tested. Clinical tissues were also tested and the results showed that these two aptamers can bind to different clinical glioma tissues but not normal brain tissues. More importantly, binding affinity and selectivity of these two aptamers were retained in complicated biological environment.

Conclusion/Significance

The selected aptamers could be used to identify specific glioblastoma biomarkers. Methods of molecular imaging, targeted drug delivery, ligand guided surgery can be further developed based on these ligands for early detection, targeted therapy, and guided surgery of glioblastoma leading to effective treatment of glioblastoma.     

In Vivo Imaging with Fluorescent Smart Probes to Assess Treatment Strategies for Acute Pancreatitis

Background and Aims

Endoprotease activation is a key step in acute pancreatitis and early inhibition of these enzymes may protect from organ damage. In vivo models commonly used to evaluate protease inhibitors require animal sacrifice and therefore limit the assessment of dynamic processes. Here, we established a non-invasive fluorescence imaging-based biomarker assay to assess real-time protease inhibition and disease progression in a preclinical model of experimental pancreatitis.

Methods

Edema development and trypsin activation were imaged in a rat caerulein-injection pancreatitis model. A fluorescent “smart” probe, selectively activated by trypsin, was synthesized by labeling with Cy5.5 of a pegylated poly-L-lysine copolymer. Following injection of the probe, trypsin activation was monitored in the presence or absence of inhibitors by in vivo and ex vivo imaging.

Results

We established the trypsin-selectivity of the fluorescent probe in vitro using a panel of endopeptidases and specific inhibitor. In vivo, the probe accumulated in the liver and a region attributed to the pancreas by necropsy. A dose dependent decrease of total pancreatic fluorescence signal occurred upon administration of known trypsin inhibitors. The fluorescence-based method was a better predictor of trypsin inhibition than pancreatic to body weight ratio.

Conclusions

We established a fluorescence imaging assay to access trypsin inhibition in real-time in vivo. This method is more sensitive and dynamic than classic tissue sample readouts and could be applied to preclinically optimize trypsin inhibitors towards intrapancreatic target inhibition.     

Icariin Ameliorates Cigarette Smoke Induced Inflammatory Responses via Suppression of NF-κB and Modulation of GR In Vivo and In Vitro

Purpose

To investigate the effects of icariin, a major constituent of flavonoids isolated from the herb Epimedium, on cigarette smoke (CS) induced inflammatory responses in vivo and in vitro.

Methods

In vivo, BALB/c mice were exposed to smoke of 15 cigarettes for 1 h/day, 6 days/week for 3 months and dosed with icariin (25, 50 and 100 mg/kg) or dexamethasone (1 mg/kg). In vitro, A549 cells were incubated with icariin (10, 50 and 100 µM) followed by treatments with CSE (2.5%).

Results

We found that icariin significantly protected pulmonary function and attenuated CS-induced inflammatory response by decreasing inflammatory cells and production of TNF-α, IL-8 and MMP-9 in both the serum and BALF of CS-exposed mice and decreasing production of TNF-α and IL-8 in the supernatant of CSE-exposed A549 cells. Icariin also showed properties in inhibiting the phosphorylation of NF-κB p65 protein and blocking the degradation of IΚB-α protein. Further studies revealed that icariin administration markedly restore CS-reduced GR protein and mRNA expression, which might subsequently contribute to the attenuation of CS-induced respiratory inflammatory response.

Conclusion

Together these results suggest that icariin has anti-inflammatory effects in cigarette smoke induced inflammatory models in vivo and in vitro, possibly achieved by suppressing NF-κB activation and modulating GR protein expression.     

Comparative Study of Nanosecond Electric Fields In Vitro and In Vivo on Hepatocellular Carcinoma Indicate Macrophage Infiltration Contribute to Tumor Ablation In Vivo

Background and Aim

Recurrence and metastasis are associated with poor prognosis in hepatocellular carcinoma even in the patients who have undergone radical resection. Therefore, effective treatment is urgently needed for improvement of patients'' survival. Previously, we reported that nanosecond pulse electric fields (nsPEFs) can ablate melanoma by induction of apoptosis and inhibition of angiogenesis. This study aims to investigate the in vivo ablation strategy by comparing the dose effect of nanosecond electric fields in vitro and in vivo on hepatocellular carcinoma.

Materials and Methods

Four hepatocellular carcinoma cell lines HepG2, SMMC7721, Hep1-6, and HCCLM3 were pulsed to test the anti-proliferation and anti-migration ability of 100 ns nsPEFs in vitro. The animal model of human subdermal xenograft HCCLM3 cells into BALB/c nude mouse was used to test the anti-tumor growth and macrophage infiltration in vivo.

Results

In vitro assays showed anti-tumor effect of nsPEFs is dose-dependant. But the in vivo study showed the strategy of low dose and multiple treatments is superior to high dose single treatment. The macrophages infiltration significantly increased in the tumors which were treated by multiple low dose nsPEFs.

Conclusion

The low dose multiple nsPEFs application is more efficient than high dose single treatment in inhibiting the tumor volume in vivo, which is quite different from the dose-effect relationship in vitro. Beside the electric field strength, the macrophage involvement must be considered to account for effect variability and toxicology in vivo.     

In vivo near-infrared imaging of fibrin deposition in thromboembolic stroke in mice

Objectives

Thrombus and secondary thrombosis plays a key role in stroke. Recent molecular imaging provides in vivo imaging of activated factor XIII (FXIIIa), an important mediator of thrombosis or fibrinolytic resistance. The present study was to investigate the fibrin deposition in a thromboembolic stroke mice model by FXIIIa–targeted near-infrared fluorescence (NIRF) imaging.

Materials and Methods

The experimental protocol was approved by our institutional animal use committee. Seventy-six C57B/6J mice were subjected to thromboembolic middle cerebral artery occlusion or sham operation. Mice were either intravenously injected with the FXIIIa-targeted probe or control probe. In vivo and ex vivo NIRF imaging were performed thereafter. Probe distribution was assessed with fluorescence microscopy by spectral imaging and quantification system. MR scans were performed to measure lesion volumes in vivo, which were correlated with histology after animal euthanasia.

Results

In vivo significant higher fluorescence intensity over the ischemia-affected hemisphere, compared to the contralateral side, was detected in mice that received FXIIIa-targeted probe, but not in the controlled mice. Significantly NIRF signals showed time-dependent processes from 8 to 96 hours after injection of FXIIIa-targeted probes. Ex vivo NIRF image showed an intense fluorescence within the ischemic territory only in mice injected with FXIIIa-targeted probe. The fluorescence microscopy demonstrated distribution of FXIIIa-targeted probe in the ischemic region and nearby micro-vessels, and FXIIIa-targeted probe signals showed good overlap with immune-fluorescent fibrin staining images. There was a significant correlation between total targeted signal from in vivo or ex vivo NIRF images and lesion volume.

Conclusion

Non-invasive detection of fibrin deposition in ischemic mouse brain using NIRF imaging is feasible and this technique may provide an in vivo experimental tool in studying the role of fibrin in stroke.     

Serial Non-Invasive Monitoring of Renal Disease Following Immune-Mediated Injury Using Near-Infrared Optical Imaging

Background

Non-invasive monitoring of disease progression in kidney disease is still a major challenge in clinical practice. In vivo near-infrared (NIR) imaging provides a new tool for studying disease mechanisms and non-invasive monitoring of disease development, even in deep organs. The LI-COR IRDye® 800CW RGD optical probe (RGD probe) is a NIR fluorophore, that can target integrin alpha v beta 3 (α_vβ₃) in tissues.

Objective

This study aims to monitor renal disease progression in an anti-glomerular basement membrane (GBM) nephritis mouse model.

Methods

Anti-GBM nephritis was induced in 129x1/svJ mice by anti-GBM serum challenge. The expression of integrin α_vβ₃ in the diseased kidney was examined by immunohistochemistry and quantitative polymerase chain reaction. The RGD probe and control fluorophores, the 800CW dye, and the BSA-conjugated 800CW dye, were administered into anti-GBM nephritic mice. LI-COR Pearl® Impulse imaging system was used for in vivo imaging; while ex vivo organ imaging was acquired using the Maestro^TM imaging system.

Results

Kidney tissue from anti-GBM nephritic mice showed higher levels of integrin α_vβ₃ expression at both the protein and the mRNA level compared to normal mice. The RGD probe allowed in vivo renal imaging and the fluorescent signal could be specifically captured in the diseased kidneys up to 14 days, reflecting longitudinal changes in renal function.

Conclusion

The infrared RGD molecular probe that tracks integrin expression can be successfully used to monitor renal disease progression following immune-mediated nephritis.     

Near Infrared Imaging of EGFR of Oral Squamous Cell Carcinoma in Mice Administered Arsenic Trioxide

Background

The effectiveness of near-infrared imaging (NIR) interrogation of epidermal growth factor receptor (EGFR) expression as a sensitive biomarker of oral squamous cell carcinoma (OSCC) response to arsenic trioxide therapy was studied in mice.

Material and Methods

A431 OSCC in vitro were exposed to 0 µM, 0.5 µM, 2.5 µM, or 5 µM of As₂O₃ for 0 h, 24 h, 48 h and 72 h. Confocal microscopy and flow cytometry confirmed EGFR expression and demonstrated a sensitivity dose-related signal decline with As₂O₃ treatment. Next, mice with pharynx-implanted A431 cells received As₂O₃ i.p. every 48 h at 0.0, 0.5, 2.5, or 5 mg/kg/day (n = 6/group) from day 0 to 10. An intravenous NIR probe, EGF-Cy5.5, was injected at baseline and on days 4, 8, and 12 for dynamic NIR imaging. Tumor volume and body weights were measured three times weekly.

Results

In vitro, A431 EGFR expression was well appreciated in the controls and decreased (p<0.05) with increasing As₂O₃ dose and treatment duration. In vivo EGFR NIR tumor signal intensity decreased (p<0.05) in As₂O₃ treated groups versus controls from days 4 to 12, consistent with increasing dosage. Tumor volume diminished in a dose-related manner while body weight was unaffected. Immunohistochemical staining of excised tumors confirmed that EGFR expression was reduced by As₂O₃ treatment in a dose responsive pattern.

Conclusion

This study demonstrates for the first time that OSCC can be interrogated in vivo by NIR molecular imaging of the EGFR and that this biomarker is effective for the longitudinal assessment of OSCC response to As₂O₃ treatment.     

DNA aptamers as molecular probes for colorectal cancer study

Background

Understanding the molecular features of specific tumors can increase our knowledge about the mechanism(s) underlying disease development and progression. This is particularly significant for colorectal cancer, which is a heterogeneous complex of diseases developed in a sequential manner through a multistep carcinogenic process. As such, it is likely that tumors with similar characteristics might originate in the same manner and have a similar molecular behavior. Therefore, specific mapping of the molecular features can be potentially useful for both tumor classification and the development of appropriate therapeutic regimens. However, this can only be accomplished by developing high-affinity molecular probes with the ability to recognize specific markers associated with different tumors. Aptamers can most easily meet this challenge based on their target diversity, flexible manipulation and ease of development.

Methodology and Results

Using a method known as cell-based Systematic Evolution of Ligands by Exponential enrichment (cell-SELEX) and colorectal cancer cultured cell lines DLD-1 and HCT 116, we selected a panel of target-specific aptamers. Binding studies by flow cytometry and confocal microscopy showed that these aptamers have high affinity and selectivity. Our data further show that these aptamers neither recognize normal colon cells (cultured and fresh), nor do they recognize most other cancer cell lines tested.

Conclusion/Significance

The selected aptamers can identify specific biomarkers associated with colorectal cancers. We believe that these probes could be further developed for early disease detection, as well as prognostic markers, of colorectal cancers.     

In Vivo Optical Imaging of Interscapular Brown Adipose Tissue with 18F-FDG via Cerenkov Luminescence Imaging

Objective

Brown adipose tissue (BAT), a specialized tissue for thermogenesis, plays important roles for metabolism and energy expenditure. Recent studies validated BAT’s presence in human adults, making it an important re-emerging target for various pathologies. During this validation, PET images with ¹⁸F-FDG showed significant uptake of ¹⁸F-FDG by BAT under certain conditions. Here, we demonstrated that Cerenkov luminescence imaging (CLI) using ¹⁸F-FDG could be utilized for in vivo optical imaging of BAT in mice.

Methods

Mice were injected with ¹⁸F-FDG and imaged 60 minutes later with open filter and 2 minute acquisition. In vivo activation of BAT was performed by norepinephrine and cold treatment under isoflurane or ketamine anesthesia. Spectral unmixing and 3D imaging reconstruction were conducted with multiple-filter CLI images.

Results

1) It was feasible to use CLI with ¹⁸F-FDG to image interscapular BAT in mice, with the majority of the signal (>85%) at the interscapular site originating from BAT; 2) The method was reliable because excellent correlations between in vivo CLI, ex vivo CLI, and ex vivo radioactivity were observed; 3) CLI could be used for monitoring BAT activation under different conditions; 4) CLI signals from the group under short-term isoflurane anesthesia were significantly higher than that from the group under long-term anesthesia; 5) The CLI spectrum of ¹⁸F-FDG with a peak at 640 nm in BAT after spectral unmixing reflected the actual context of BAT; 6) Finally 3D reconstruction images showed excellent correlation between the source of the light signal and the location and physical shape of BAT.

Conclusion

CLI with ¹⁸F-FDG is a feasible and reliable method for imaging BAT in mice. Compared to PET imaging, CLI is significantly cheaper, faster for 2D planar imaging and easier to use. We believe that this method could be used as an important tool for researchers investigating BAT.     

First report of in vitro selection of RNA aptamers targeted to recombinant Loxosceles laeta spider toxins

Background

Loxoscelism is the envenomation caused by the bite of Loxosceles spp. spiders. It entails severe necrotizing skin lesions, sometimes accompanied by systemic reactions and even death. There are no diagnostic means and treatment is mostly palliative. The main toxin, found in several isoforms in the venom, is sphingomyelinase D (SMD), a phospholipase that has been used to generate antibodies intended for medical applications. Nucleic acid aptamers are a promising alternative to antibodies. Aptamers may be isolated from a combinatorial mixture of oligonucleotides by iterative selection of those that bind to the target. In this work, two Loxosceles laeta SMD isoforms, Ll1 and Ll2, were produced in bacteria and used as targets with the aim of identifying RNA aptamers that inhibit sphingomyelinase activity.

Results

Six RNA aptamers capable of eliciting partial but statistically significant inhibitions of the sphingomyelinase activity of recombinant SMD-Ll1 and SMD-Ll2 were obtained: four aptamers exert ~17% inhibition of SMD-Ll1, while two aptamers result in ~25% inhibition of SMD-Ll2 and ~18% cross inhibition of SMD-Ll1.

Conclusions

This work is the first attempt to obtain aptamers with therapeutic and diagnostic potential for loxoscelism and provides an initial platform to undertake the development of novel anti Loxosceles venom agents.     

Bioluminescent orthotopic mouse models of human localized non-small cell lung cancer: feasibility and identification of circulating tumour cells

Background

Preclinical models of non-small cell lung cancer (NSCLC) require better clinical relevance to study disease mechanisms and innovative therapeutics. We sought to compare and refine bioluminescent orthotopic mouse models of human localized NSCLC.

Methods

Athymic nude mice underwent subcutaneous injection (group 1-SC, n = 15, control), percutaneous orthotopic injection (group 2-POI, n = 30), surgical orthotopic implantation of subcutaneously grown tumours (group 3-SOI, n = 25), or transpleural orthotopic injection (group 4-TOI, n = 30) of A549-luciferase cells. Bioluminescent in vivo imaging was then performed weekly. Circulating tumour cells (CTCs) were searched using Cellsearch® system in SC and TOI models.

Results

Group 2-POI was associated with unexpected direct pleural spreading of the cellular solution in 53% of the cases, forbidding further evaluation of any localized lung tumour. Group 3-SOI was characterized by high perioperative mortality, initially localized lung tumours, and local evolution. Group 4-TOI was associated with low perioperative mortality, initially localized lung tumours, loco regional extension, and distant metastasis. CTCs were detected in 83% of nude mice bearing subcutaneous or orthotopic NSCLC tumours.

Conclusions

Transpleural orthotopic injection of A549-luc cells in nude mouse lung induces localized tumour, followed by lymphatic extension and specific mortality, and allowed the first time identification of CTCs in a NSCLC mice model.     

Thyroid Cancer Imaging In Vivo by Targeting the Anti-Apoptotic Molecule Galectin-3

Background

The prevalence of thyroid nodules increases with age, average 4–7% for the U.S.A. adult population, but it is much higher (19–67%) when sub-clinical nodules are considered. About 90% of these lesions are benign and a reliable approach to their preoperative characterization is necessary. Unfortunately conventional thyroid scintigraphy does not allow the distinction among benign and malignant thyroid proliferations but it provides only functional information (cold or hot nodules).The expression of the anti-apoptotic molecule galectin-3 is restricted to cancer cells and this feature has potential diagnostic and therapeutic implications. We show here the possibility to obtain thyroid cancer imaging in vivo by targeting galectin-3.

Methods

The galectin-3 based thyroid immuno-scintigraphy uses as radiotracer a specific ^99mTc-radiolabeled mAb. A position-sensitive high-resolution mini-gamma camera was used as imaging capture device. Human galectin-3 positive thyroid cancer xenografts (ARO) and galectin-3 knockout tumors were used as targets in different experiments in vivo. 38 mice with tumor mass of about 1 gm were injected in the tail vein with 100 µCi of ^99mTc-labeled mAb to galectin-3 (30 µg protein/in 100 µl saline solution). Tumor images were acquired at 1 hr, 3 hrs, 6 hrs, 9 hrs and 24 hrs post injection by using the mini-gamma camera.

Findings

Results from different consecutive experiments show an optimal visualization of thyroid cancer xenografts between 6 and 9 hours from injection of the radiotracer. Galectin-3 negative tumors were not detected at all. At 6 hrs post-injection galectin-3 expressing tumors were correctly visualized, while the whole-body activity had essentially cleared.

Conclusions

These results demonstrate the possibility to distinguish preoperatively benign from malignant thyroid nodules by using a specific galectin-3 radio-immunotargeting. In vivo imaging of thyroid cancer may allow a better selection of patients referred to surgery. The possibility to apply this method for imaging and treatment of other galectin-3 expressing tumors is also discussed.     

Increased Migration of Human Mesenchymal Stromal Cells by Autocrine Motility Factor (AMF) Resulted in Enhanced Recruitment towards Hepatocellular Carcinoma

Background and Aims

Several reports described the migration of human mesenchymal stromal cells (MSCs) towards tumor-released factors. Autocrine motility factor (AMF) is produced by several tumors including hepatocellular carcinoma (HCC). The aim of this study was to analyze AMF involvement on MSC migration towards human HCC.

Methods

Production of AMF by HCC tumors was evaluated by western analysis. The effects of AMF on MSCs from different sources (bone marrow, adipose tissue and perivascular cells from umbilical cord) were analyzed using in vitro migration assay; metalloproteinase 2 (MMP2) activity and expression of critical genes were studied by zymography and qRT-PCR, respectively. To assess AMF involvement on the in vivo MSC migration, noninvasive fluorescence imaging was performed. To test the effect of AMF-primed MSCs on tumor development, in vitro proliferation and spheroids growth and in vivo tumor volume were evaluated.

Results

AMF produced by HCC was found to induce migration of different MSCs in vitro and to enhance their MMP2 activity. Stimulation of MSCs with recombinant AMF (rAMF) also induced the in vitro adhesion to endothelial cells in coincidence with changes in the expression levels of MMP3, AMF receptor, caveolin-1, and -2 and GDI-2. Importantly, stimulation of MSCs with rAMF increased the in vivo migration of MSCs towards experimental HCC tumors. AMF-priming of MSCs did not induce a pro-tumorigenic effect on HCC cells neither in vivo nor in vitro.

Conclusion

AMF plays a role in MSC recruitment towards HCC. However, its ability to increase MSC migration to HCC for therapeutic purposes merits further evaluation.     

Study of the molecular recognition of aptamers selected through ovarian cancer cell-SELEX

Background

Ovarian cancer is the most lethal gynecological malignancy, and the ovarian clear cell carcinoma subtype (OCCA) demonstrates a particularly poor response to standard treatment. Improvements in ovarian cancer outcomes, especially for OCCA, could be expected from a clearer understanding of the molecular pathology that might guide strategies for earlier diagnosis and more effective treatment.

Methodology/Principal Findings

Cell-SELEX technology was employed to develop new molecular probes for ovarian cancer cell surface markers. A total of thirteen aptamers with K_d''s to ovarian cancer cells in the pico- to nanomolar range were obtained. Preliminary investigation of the targets of these aptamers and their binding characteristics was also performed.

Conclusions/Significance

We have selected a series of aptamers that bind to different types of ovarian cancer, but not cervical cancer. Though binding to other cancer cell lines was observed, these aptamers could lead to identification of biomarkers that are related to cancer.