Author Correction: RNA cargos in extracellular vesicles derived from blood serum in pancreas associated conditions.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

RNA cargos in extracellular vesicles derived from blood serum in pancreas associated conditions.

Exosomes are extracellular vesicles which are released from healthy and tumor cells into blood circulation. Unique biomolecular cargos such as RNA and protein are loaded in these vesicles. These molecules may have biological functions such as signaling, cell communications and have the potential to be analyzed as biomarkers. In this initial study, we describe the analysis of exosomes in the serum of healthy subjects, intraductal papillary mucosal neoplasms and pancreatic ductal adenocarcinoma including the characterization of their RNA cargos by next generation sequencing (EXO-NGS). Results indicate the presence of a wide variety of RNAs including mRNA, miRNA, lincRNA, tRNA and piRNA in these vesicles. Based on the differential mRNA expression observed upon EXO-NGS analysis, we independently evaluated two protein coding genes, matrix metalloproteinase-8 (MMP-8) and transcription factor T-Box 3 (TBX3) by qRT-PCR for selective expression in the serum samples. Results indicate a variable expression pattern of these genes across serum samples between different study groups. Further, qRT-PCR analysis with the same serum exosomes processed for EXO-NGS, we observed two long non-coding RNAs, malat-1 and CRNDE to be variably expressed. Overall, our observations emphasize the potential value of different exosome components in distinguishing between healthy, premalignant and malignant conditions related to the pancreas.

Molecular targets for tivantinib (ARQ 197) and vasculogenic mimicry in human melanoma cells.

Tivantinib (TivB) was reported previously to target MET and microtubule assembly in different cells resulting in cytotoxicity. However, its other cellular targets remain unknown, especially the proteins involved in focal adhesion and cytoskeletal organization. We studied the effect of TivB on vinculin a focal adhesion protein, and RhoC, a GTPase which promote the reorganization of cytoskeleton. Biomolecules involved in vasculogenic mimicry (VM) previously not reported in melanoma, and their susceptibility to TivB was also evaluated. TivB affects the viability and apoptosis of human melanoma cells depending on the cell type. Vinculin and RhoC were increased in the presence of TivB and affected the integrity of actin filaments and altered the cellular morphology. TivB disrupts the VM exhibited by melanoma cells in 3D matrix. Roundabout Guidance Receptor 4 (Robo4), a receptor protein implicated in axonal guidance and angiogenesis and its ligand Slit2 are expressed in human C8161 and WM793 melanoma cells, but absent in other melanoma cells including normal melanocytes. VM is more prominent in C8161 cells and could be blocked by siRNA mediated silencing of Robo4 mRNA, but TivB does not affect Robo4 in C8161 cells. Immunoblot analysis indicated no changes in Robo4 and Slit2 protein expression, however, both vinculin and RhoC protein increased in TivB treated melanoma cells. These results suggest that TivB affects cell cytoskeleton and morphology by altering proteins such as vinculin and RhoC. Our studies indicate TivB could target molecules other than MET in melanoma cells, which may provide insight into its alternate mechanism of action.

Differential Modulation of Transcription Factors and Cytoskeletal Proteins in Prostate Carcinoma Cells by a Bacterial Lactone.

The present study tested the effect of a bacterial lactone N-(3-oxododecanoyl)-homoserine lactone (C12-HSL) on the cytoskeletal and transcriptional genes and proteins in prostate adenocarcinoma (PA) cells (DU145 and LNCaP) and prostate small cell neuroendocrine carcinoma (SCNC) PC3 cells including their cellular viability and apoptosis. Our data indicate that cell migration and colony formation were affected in the presence of C12-HSL. C12-HSL induced apoptosis and altered viability of both PA and SCNC cells in a concentration dependent manner as measured by fluorescence and chemiluminescence assays. Compared to PCa cells, noncancerous prostate epithelial cells (RWPE1) were resistant to modification by C12-HSL. Further, the viability of PC3 cells in 3D matrix was suppressed by C12-HSL treatment as detected using calcein AM fluorescence in situ. C12-HSL treatment induced cytoskeletal associated protein expression of vinculin and RhoC, which may have implications in cancer cell motility, adhesion, and metastasis. IQGAP protein expression was reduced in DU145 and RWPE1 cells in the presence of C12-HSL. C12-HSL decreased STAT3 phosphorylation in DU145 cells but increased STAT1 protein phosphorylation in PC3 and LNCaP cells. Overall, these studies indicate that C12-HSL can trigger changes in transcription factors and cytoskeletal proteins and thereby modulate growth and migration properties of PCa cells.

Testis specific Y-like 5: gene expression, methylation and implications for drug sensitivity in prostate carcinoma.

BACKGROUND: TSPYL5, a putative tumor suppressor gene, belongs to the nucleosome assembly protein family. The chromosomal location of the TSPYL5 gene is 8Q22.1, and its exact role in prostate cancer etiology remains unclear. Further TSPYL5 gene and protein expression in prostate carcinoma cells and diseased tissues including its susceptibility for epigenetic silencing is unknown. Also, not known is the variation in TSPYL5 protein expression with regards to progression of prostatic carcinoma and its possible role in drug sensitivity. METHODS: TSPYL5, DNMT-1 and DNMT-B gene expression in DU145, LNCaP and RWPE-1 cells and prostate tumor tissues was analyzed by qRT-PCR and RT-PCR. Demethylation experiments were done by treating DU145 and LNCaP cells with 5-aza-2'-deoxycytidine in vitro. Methylation analysis of TSPYL5 gene was performed by methylation specific PCR and pyrosequencing. TSPYL5 protein expression in benign and diseased prostate tumor tissues was performed by immunohistochemistry and in the cells by Western blotting. RESULTS: TSPYL5 was differentially expressed in non-tumorigenic prostate epithelial cells (RWPE-1), androgen independent (DU145), dependent (LNCaP) prostate carcinoma cells and tissues. Methylation-specific PCR and pyrosequencing analysis identified an inverse relationship between DNA methylation and expression leading to the silencing of TSPYL5 gene. Treatment of prostate carcinoma cells in which TSPYL5 was absent or low (DU145 and LNCaP) with the demethylating agent 5-aza-2'-deoxycytidine upregulated its expression in these cells. Immunohistochemical studies clearly identified TSPYL5 protein in benign tissue and in tumors with Gleason score (GS) of 6 and 7. TSPYL5 protein levels were very low in tumors of GS ≥ 8. TSPYL5 overexpression in LNCaP cells increased the cell sensitivity to chemotherapy drugs such as docetaxel and paclitaxel, as measured by the cellular viability. Furthermore, the cells also exhibited reduced CDKN1A expression with only marginal reduction in pAKT. CONCLUSIONS: Decrease in TSPYL5 protein in advanced tumors might possibly function as an indicator of prostate tumor progression. Its absence due to methylation-induced silencing can lead to reduced drug sensitivity in prostate carcinoma.

Peroxisome proliferator activated receptor γ protein expression is asymmetrically distributed in primary lung tumor and metastatic to lung osteosarcoma samples and does not correlate with gene methylation.

BACKGROUND: Peroxisome proliferator activated receptor-γ (PPAR-γ) is a ligand-dependent transcription factor that plays important roles in cellular proliferation and differentiation. It has been implicated as a tumor suppressor in many solid tumors including human prostate, breast, colon, and lung cancer. The objective of this study was to determine the tissue distribution of PPAR-γ in normal canine lung, canine lung cancer, and metastatic to lung cancer, as well as determine the role, if any, of DNA methylation in epigenetic control of gene expression. The protein was studied using immunohistochemistry (IHC) and DNA methylation was studied using combined bisulfite restriction analysis (COBRA), and methylation-specific PCR (MSP). RESULTS: PPAR-γ is expressed in all large conducting airways, particularly in goblet cells and bronchial glands, in the canine lung. The protein is also expressed in interstitial macrophages. PPAR-γ is expressed in 33 % of canine non-small cell lung cancer (NSCLC) cases and 66 % of metastatic osteosarcoma (OSA) cases. There is a significant loss of 5' PPAR-γ methylation from normal lung to primary lung cancer and metastatic OSA (p = 0.0002), however altered PPAR-γ promoter methylation at the interrogated locus does not appear to be associated with changes in protein expression. CONCLUSIONS: PPAR-γ protein is expressed in normal canine lung tissue, canine primary lung cancer, and metastatic OSA. Confirmation of PPAR-γ protein expression in tumor-bearing dogs supports the investigation of PPAR-γ agonists in this subset of veterinary patients. These results are the first to describe epigenetic marks and protein localization of PPAR-γ among different lung pathologies in the dog.

6-Thioguanine and zebularine down-regulate DNMT1 and globally demethylate canine malignant lymphoid cells.

BACKGROUND: The antimetabolite 6-thioguanine (6-TG) has been used to treat both human and canine lymphoid malignancies. 6-TG has been shown to be epigenetically active as a demethylating agent in a human lymphoma cell line, causing downregulation of DNA methyltransferase 1 (DNMT1) through ubiquitin-targeted degradation. Zebularine (Zeb), a similar cytidine analog, also has demethylating activity as well as oral bioavailability. The hypothesis of the present study was that 6-TG and Zeb would cause downregulation of DNMT1 and globally demethylate the genomic DNA of canine lymphoma cells. The secondary hypothesis was that these agents would cause a dose-dependent decrease in cell proliferation in canine lymphoma cells. Canine CLGL-90 malignant T cells and CLL 17-7 cells were incubated in modified RPMI media. They were treated with 6-TG, Zeb, or control media at biologically relevant concentrations. RESULTS: Following treatment with each agent, DNMT1 protein and global DNA methylation were significantly decreased. A dose-dependent decrease in cell survival was also observed, with apoptosis being the primary mode of cell death in the CLGL-90 cell line. CONCLUSIONS: These results confirm the demethylating action of 6-TG and Zeb in canine cells which is similar to that shown in human cell lines. Confirmation of this mechanism supports the clinical application of these compounds as demethylating drugs in veterinary patients.

Bacterial quorum sensing molecule N-3-oxo-dodecanoyl-L-homoserine lactone causes direct cytotoxicity and reduced cell motility in human pancreatic carcinoma cells.

In spite of chemotherapeutic and surgical advances, pancreatic cancer continues to have a dismal prognosis. Metastasis due to tumor cell migration remains the most critical challenge in treating pancreatic cancer, and conventional chemotherapy is rarely curative. In the quest for more novel molecules to fight this disease, we tested the hypothesis that the Pseudomonas aeruginosa quorum sensing signal molecule N-3-oxo-dodecanoyl-L-homoserine lactone (O-DDHSL) would be cytotoxic to and reduce mobility of pancreatic carcinoma cells (Panc-1 and Aspc-1). Results showed a decrease in cell viability from apoptosis, diminished colony formation, and inhibition of migration of the evaluated pancreatic carcinoma cell lines. Also, cell viability decreased in the presence of O-DDHSL when cells were grown in matrigel basement membrane matrix. While messenger RNA for IQGAP-1 decreased in Panc-1 and HPDE cells upon exposure to O-DDHSL, no change was observed in Aspc-1 cells. Cofilin mRNA expression was found to be increased in both HPDE and Panc-1 cells with marginal decrease in Aspc-1 cells. RhoC, a Rho-family GTPase involved in cell motility, increased in the presence of O-DDHSL, suggesting a possible compensatory response to alteration in other migration associated genes. Our results indicate that O-DDHSL could be an effective biomolecule in eukaryotic systems with multimodal function for essential molecular targeting in pancreatic cancer.

In vivo bacteriophage peptide display to tailor pharmacokinetics of biological nanoparticles.

PURPOSE: Clinical use of most radiolabeled targeting agents has been limited because of the uptake and retention in kidney and/or liver. We hypothesized that bacteriophage (phage) display could be exploited to select for peptide sequences with fast clearance and low kidney uptake with the added ability to redirect phage clearance away from the reticuloendothelial system towards the kidney possessing rapid kidney clearance. PROCEDURES: In vivo phage display was performed to identify peptides displayed on phage that were excreted rapidly into the urine of mice. A novel in vitro assay using kidney cells, developed to predict in vivo kidney retention, and in vivo pharmacokinetic analyses were performed to characterize selected peptides/phage clones. RESULTS: Forty-three renal clearance clones (RCC) were identified. In vivo mixing experiments and in vitro kidney cell assays identified RCC1-02 as the lead compound. In vivo analysis of fluorescently labeled phage clones demonstrated the ability of RCC1-02 peptide to redirect the biodistribution of the large phage particle towards excretion via the kidney. Pharmacokinetic analysis of [(111)In]-radiolabeled peptides revealed that kidney retention of the control ErBB-2-avid peptide, [(111)In]DOTA-KCCYSL, at 2-h postinjection was 5.7 ± 0.7 %ID/g. In comparison, [(111)In]DOTA-RCC1-02 had kidney retention values of 1.66 ± 0.43 %ID/g, respectively. CONCLUSIONS: In vivo phage display can identify phage and corresponding peptides that rapidly clear the renal system. In the future, these peptides may be used to impart favorable pharmacokinetics onto a wide range of radioimaging or therapeutic macromolecules.

Zebularine significantly sensitises MEC1 cells to external irradiation and radiopharmaceutical therapy when administered sequentially in vitro.

Zebularine is a cytidine analogue incorporated into DNA during replication, inhibiting DNA methyltransferase 1 (DNMT1), resulting in demethylation and changes in gene expression. Such modification may improve radiosensitivity in resistant lymphoma cells. The hypothesis of this study was that zebularine and radiation would synergistically inhibit cell growth and viability. Human MEC1 malignant B cells were incubated with 0-200 µM zebularine for 48 h. Media containing zebularine was removed, and the cells were irradiated with 0-2 Gy of either external beam irradiation or (177) Lu-DOTA-TATE, a radiolabelled somatostatin analogue. Concentration and viability were measured over 48-72 h. The proportion of apoptotic cells was identified using an active Caspase 3/7 assay. Zebularine inhibited growth of cells in a dose-dependent manner during exposure. No residual growth inhibition occurred following removal of the drug. Zebularine and external irradiation inhibited cell proliferation in a dose-dependent, synergistic interaction, but the effect on viability was additive. Treatment with zebularine and (177) Lu-DOTA-TATE resulted in less inhibition of proliferation (P = 0.0135), but a synergistic decrease in viability. Apoptotic fraction was much higher in cells irradiated with (177) Lu-DOTA-TATE than external irradiation. External irradiation induces growth arrest rather than apoptosis. Apoptosis is the primary effect of radiopharmaceutical therapy on tumour cells. Treatment with the methylation inhibitor, zebularine, appears to synergistically augment these natural effects in vitro, which could be exploited clinically.

The health effects of fetal microchimerism can be modeled in companion dogs.

Fetal microchimerism (FMC) has been described to have a range of effects on health and disease. Y-chromosomal DNA has been detected in Golden Retrievers suggesting persistent FMC. In that report, nine dogs had evidence of microchimerism without prior pregnancy. To further understand this finding, a dam with prior male live births giving birth to her fourth litter of puppies, all females, was evaluated for FMC along with two of her daughters. All three female dogs had evidence of Y-chromosomal DNA in their blood. This suggests that male cells carried by the dam from previous pregnancy trafficked to her daughters to establish microchimerism in younger siblings. Companion dogs share many of the same cancers as humans, have out-bred genetics, and share the human environment, making them optimal models of human disease. Understanding the impact of FMC on health and disease of dogs could elucidate mechanisms useful for clinical interventions in humans.

Nanoparticulate paclitaxel demonstrates antitumor activity in PC3 and Ace-1 aggressive prostate cancer cell lines.

BACKGROUND: Paclitaxel is an effective antimitotic agent in cancer treatment; however, one of its most common toxicities is hypersensitivity due to excipients used for water solubility. Nanoparticulate paclitaxel (Crititax®, CTI52010) is paclitaxel that consists only of nanoparticulate drug in saline. Our objective was to examine the effect of nanoparticulate paclitaxel on prostate cancer cells derived from castration-resistant prostate cancer in men and dogs, as companion dogs represent a unique naturally occurring model of castration-resistant prostate cancer. We hypothesized that nanoparticulate paclitaxel would be effective in affecting cell viability, colony forming ability, apoptosis, and induction of structural changes to the microtubules of prostate cancer cells. METHODS: Human PC3 and canine Ace-1 cells were treated with 0.001-1.0 µm concentrations of paclitaxel and nanoparticulate paclitaxel. Cell viability, apoptosis, and colony forming assays were analyzed and compared in the presence of both drugs. Microtubule structure was examined by fluorescence microscopy following incubation with drug. RESULTS: Nanoparticulate paclitaxel was as effective as standard paclitaxel in decreasing cell viability, decreasing colony forming ability, and inducing apoptosis in human and canine prostate cancer cells in a dose-dependent manner. Fluorescence microscopy confirmed the microtubule target of nanoparticulate paclitaxel. CONCLUSIONS: Nanoparticulate paclitaxel is as effective as paclitaxel in decreasing cell viability, initiating apoptosis, decreasing cell survival, and causing rigidity of microtubules in both human and canine castration-resistant prostate cancer. This represents an attractive area for further study, using the companion dog as a model for disease in men.

Y-chromosome DNA is present in the blood of female dogs suggesting the presence of fetal microchimerism.

Fetal microchimerism has been suggested to play contradictory roles in women's health, with factors including age of the recipient, time elapsed since microchimerism occurred, and microchimeric cell type modulating disease. Both beneficial and harmful effects have been identified in wound healing and tissue regeneration, immune mediated disease, and cancer. This area of research is relatively new, and hindered by the time course from occurrence of fetal microchimerism to the multi-factorial development of disease. Dogs represent an excellent model for study of fetal microchimerism, as they share our environment, have a naturally condensed lifespan, and spontaneously develop immune-mediated diseases and cancers similar to their human counterparts. However, fetal microchimerism has not been described in dogs. These experiments sought preliminary evidence that dogs develop fetal microchimerism following pregnancy. We hypothesized that Y chromosomal DNA would be detected in the peripheral blood mononuclear cells of female dogs collected within two months of parturition. We further hypothesized that Y chromosomal DNA would be detected in banked whole blood DNA samples from parous female Golden Retrievers with at least one male puppy in a prior litter. Amplification of DNA extracted from five female Golden Retrievers that had whelped within the two months prior to collection revealed strong positive bands for the Y chromosome. Of banked, parous samples, 36% yielded positive bands for the Y chromosome. This is the first report of persistent Y chromosomal DNA in post-partum female dogs and these results suggest that fetal microchimerism occurs in the canine species. Evaluation of the contributions of fetal microchimeric cells to disease processes in dogs as a model for human disease is warranted.

(64)Cu-labeled peptide for PET of breast carcinomas expressing the Thomsen-Friedenreich carbohydrate antigen.

UNLABELLED: Thomsen-Friedenreich (TF) antigen is a disaccharide, galactose ß1-3 N-acetylgalactosamine (Galß1-3GalNAc), expressed on the cell surfaces of most human carcinomas including breast. In this study, we synthesized and evaluated the in vitro and in vivo properties of a (64)Cu-radiolabeled TF antigen-specific peptide derived from bacteriophage display for the purpose of breast tumor targeting and PET of human breast tumors in xenografted mice. METHODS: The TF antigen-specific peptide IVWHRWYAWSPASRI was synthesized with the chelator 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) at the amino terminus, followed by a Gly-Ser-Gly (GSG) spacer. Amino acids Asp and Arg were introduced at both ends to enhance its solubility. Purified NO2A-GSG-DRD-IVWHRWYAWSPASRI-DRD (NO2A-TFpep) was radiolabeled with (64)Cu and evaluated for binding to human MDA-MB-435 breast cancer cells, 50% inhibitory concentration (IC(50)), and serum stability. In vivo pharmacokinetic and small-animal PET studies were performed using SCID mice bearing MDA-MB-435 tumor xenografts. RESULTS: (64)Cu-NO2A-TFpep bound to human MDA-MB-435 breast carcinoma cells, whereas almost no binding was observed to normal human breast 184A1 cells. The peptide exhibited an apparent IC(50) value of 70 ± 8.0 nM. In vivo biodistribution studies indicated radiolabeled peptide accumulation in tumors of MDA-MB-435 xenografted SCID mice of approximately 1.10 ± 0.20 percentage injected dose per gram (%ID/g) and 0.90 ± 0.12 %ID/g, at 0.5 and 1 h, respectively. Accumulation of radioactivity was low in other organs, with the exception of liver (1.52 ± 0.12 %ID/g) and kidneys (15.4 ± 1.73 %ID/g) at 1 h. Live imaging studies with (64)Cu-NO2A-TFpep (15 MBq) demonstrated good tumor uptake at 1 h after injection, whereas no tumor uptake was observed with a scrambled radiolabeled peptide (64)Cu-NO2A-GSG-DRD-RWSWWAVHRIPYSAI-DRD. CONCLUSION: (64)Cu-NO2A-TFpep may function as a noninvasive in vivo tumor imaging agent of human breast and other carcinomas expressing the TF carbohydrate antigen. This is the first such TF antigen-targeting peptide used in tumor imaging.

Carbohydrate antigens in nipple aspirate fluid predict the presence of atypia and cancer in women requiring diagnostic breast biopsy.

BACKGROUND: The goal of this prospective study was to determine (a) concentrations of the carbohydrate biomarkers Thomsen Friedenreich (TF) antigen and its precursor, Tn antigen, in nipple discharge (ND) collected from women requiring biopsy because of a suspicious breast lesion; and (b) if concentration levels predicted pathologic diagnosis. METHODS: Adult women requiring biopsy to exclude breast cancer were enrolled and ND obtained. The samples from 124 women were analyzed using an anti-TF and anti-Tn monoclonal antibodies in direct immunoassay. RESULTS: The highest median concentration in ND for TF and Tn was in women with ductal carcinoma in situ (DCIS). TF was higher in women with 1) cancer (DCIS or invasive) vs. either no cancer (atypia or benign pathology, p = .048), or benign pathology (p = .018); and 2) abnormal (atypia or cancer) versus benign pathology (p = .016); and was more predictive of atypia or cancer in post- compared to premenopausal women. Tn was not predictive of disease. High TF concentration and age were independent predictors of disease, correctly classifying either cancer or abnormal vs. benign pathology 83% of the time in postmenopausal women. CONCLUSIONS: TF concentrations in ND were higher in women with precancer and cancer compared to women with benign disease, and TF was an independent predictor of breast atypia and cancer. TF may prove useful in early breast cancer detection.

In vitro and in vivo evaluation of 64Cu-radiolabeled KCCYSL peptides for targeting epidermal growth factor receptor-2 in breast carcinomas.

Epidermal growth factor receptor-2 (EGFR-2) has been implicated in the pathogenesis of breast and other carcinomas. In this report, we tested the ability of a bacteriophage selected peptide KCCYSL, radiolabeled with 64Cu, to image EGFR-2 expressing breast tumors in vivo by positron emission tomography (PET). We evaluated and compared the in vivo tissue distribution and imaging properties of 64Cu-X-(Gly-Ser-Gly)-KCCYSL peptide (X = 1,4,7,10, tetraazacyclododecane-N,N',N'',N'''-tetracetic acid, [DOTA] 1,4,8,11-tetraazabicyclo[6.6.2]hexadecane-4,11-diacetic acid [CB-TE2A], and 1,4,7-triazacyclononane-1,4,7-triacetic acid [NOTA] chelators) in a human breast cancer xenograft mouse model using dual modality PET and computed tomography (CT). The synthesized peptides DO3A-GSG-KCCYSL, CB-TE2A-GSG-KCCYSL, and NO2A-GSG-KCCYSL were purified, radiolabeled with 64Cu, and evaluated for human breast cancer cell (MDA-MB-435) binding, 50% inhibitory concentration, and serum stability. In vivo pharmacokinetic and small animal PET/CT imaging studies were performed using SCID mice bearing MDA-MB-435 xenografts. The radiolabeled peptides bound with an 50% inhibitory concentration of 42.0 ± 10.2 nM (DO3A), 31 ± 7.9 nM (CB-TE2A), and 44.2 ± 6.6 nM (NO2A) to cultured MDA-MB-435 cells. All of the radiolabeled peptides were stable in vitro. The tumor uptake of DO3A, CB-TE2A, and NO2A peptides were 0.73 ± 0.15 percent injected dose per gram (%ID/g), 0.64 ± 0.08%ID/g, and 0.52 ± 0.04%ID/g, respectively at 1 hour. Liver uptake for the 64Cu-DO3A-peptide (1.68 ± 0.42%ID/g) was more than that of the 64Cu-CB-TE2A-peptide (0.52 ± 0.02% ID/g) and 64Cu-NO2A-peptide (0.48 ± 0.05%ID/g) at 2 hours. PET/CT studies revealed successful tumor uptake of 64Cu-peptides at 2 hours postinjection. In vivo kidney retention was observed with all of the radiolabeled peptides. The optimization of bifunctional chelators improves the pharmacokinetic properties of the 64Cu-labeled GSG-KCCYSL peptide, which enables the selection of a suitable peptide homolog as a PET imaging agent for EGFR-2 expressing breast carcinomas.

Tumor targeting and SPECT imaging properties of an (111)In-labeled galectin-3 binding peptide in prostate carcinoma.

INTRODUCTION: Galectin-3 (gal-3) is a carbohydrate binding protein that has been implicated in cell adhesion, tumor invasion and metastasis. The objective of this study was to evaluate the tumor targeting and imaging properties of a gal-3 binding peptide selected by phage display in a mouse model of metastatic human prostate carcinoma expressing gal-3. METHODS: A gal-3 binding peptide, ANTPCGPYTHDCPVKR, was synthesized with a Gly-Ser-Gly (GSG) spacer and 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA) and then radiolabeled with (111)In. The in vitro cell binding properties of (111)In-DOTA-(GSG)-ANTPCGPYTHDCPVKR were determined in metastatic human PC3-M prostate carcinoma cells. The pharmacokinetics and single-photon emission computed tomographic (SPECT/CT) imaging with the radiolabeled peptide were evaluated in SCID mice bearing human PC3-M prostate carcinoma tumor xenografts. RESULTS: The radiolabeled peptide bound with a 50% inhibitory concentration of 191+/-10.2 nM to cultured PC3-M prostate carcinoma cells. In vivo tumor uptake and retention coupled with fast whole-body clearance of the peptide were demonstrated in PC3-M tumor-bearing SCID mice. The tumor uptake rates of the radiolabeled peptide were 1.27+/-0.10%ID/g at 30 min, 0.82+/-0.15%ID/g at 1 h and 0.57+/-0.09%ID/g at 2 h. MicroSPECT/CT studies revealed good tumor uptake of (111)In-DOTA-(GSG)-ANTPCGPYTHDCPVKR 2 h postinjection, while uptake in normal organs was low, with the exception of the kidneys. CONCLUSIONS: In vitro cell binding along with tumor uptake of (111)In-DOTA-(GSG)-ANTPCGPYTHDCPVKR in PC3-M human prostate carcinoma tumor-bearing SCID mice suggests the potential of this peptide as a radiopharmaceutical for imaging of gal-3-expressing prostate tumors.

In-labeled KCCYSL peptide as an imaging probe for ErbB-2-expressing ovarian carcinomas.

Aberrant expression of ErbB-2, a member of the epidermal growth factor family of receptors, has been implicated in the formation of various malignancies including ovarian cancer. The objective of this study was to determine if the bacteriophage (phage) display-selected ErbB-2 targeting peptide, KCCYSL, once radiolabeled with (111)In would serve as a tumor targeting and Single Photon Emission Computed Tomography (SPECT/CT) imaging agent in a mouse model of human ovarian carcinoma expressing ErbB-2. The KCCYSL peptide was synthesized with a chelator 1,4,7,10-tetra-azacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA), and a Gly-Ser-Gly (GSG) spacer between DOTA and amino terminus of the peptide and radiolabeled with (111)InC1(3). In vitro cell binding studies indicated that (111)In-DOTA-GSG-KCCYSL bound to cultured ovcar-3 carcinoma cells. Biodistribution studies in scid mice bearing human ovcar-3 tumor xenografts revealed a tumor uptake of 0.50 ± 0.05 percent injected dose per gram (%ID/g) at 1 h, and 0.39 ± 0.1 %ID/g at 2 h. Blocking studies with non-radiolabeled counterpart indicated a partial inhibition (41%) (P = 0.04) in tumor uptake of (111)In-DOTA-GSG-KCCYSL. In vivo tumor uptake of (111)In-DOTA-GSG-KCCYSL was clearly evident through SPECT/CT images after 2 h post injection. These studies suggest the potential of this peptide as a radiopharmaceutical for imaging of ErbB-2-expressing ovarian tumors.

111In-labeled galectin-3-targeting peptide as a SPECT agent for imaging breast tumors.

UNLABELLED: Galectin-3 is a member of the galectin family of beta-galactoside-binding animal lectins. Galectin-3 is overexpressed in a wide range of neoplasms and is associated with tumor growth and metastases. Given this fact, radiolabeled galectin-3-targeting molecules may be useful for the noninvasive imaging of tumors expressing galectin-3, as well as for targeted radionuclide therapy. In this study, the tumor cell-targeting and SPECT properties of a galectin-3-avid peptide identified from bacteriophage display were evaluated in human breast carcinoma cells and in human breast tumor-bearing mice. METHODS: The galectin-3-avid peptide G3-C12 (ANTPCGPYTHDCPVKR) was synthesized with a Gly-Ser-Gly (GSG) linker at the amino terminus. After conjugation with 1,4,7,10-tetra-azacyclododecane-N,N',N''N'''-tetraacetic acid (DOTA), the peptide was labeled with (111)In. The radiochemical purity and stability of the compound was assessed by high-performance liquid chromatography. MDA-MB-435 human breast carcinoma cells expressing galectin-3 were used to characterize the in vitro binding properties of the radiolabeled compound. SCID mice bearing MDA-MB-435 xenografts were used as an in vivo model for biodistribution and imaging studies with the (111)In-labeled peptide. RESULTS: (111)In-DOTA(GSG)-G3-C12 bound specifically to galectin-3-expressing MDA-MB-435 cells. The radiolabeled peptide was stable in serum and was found intact in excreted urine for at least 1 h. Competitive binding experiments indicated that the radiolabeled peptide exhibited an inhibitory concentration of 50% of 200.00+/-6.70 nM for cultured breast carcinoma cells. In vivo biodistribution studies revealed that tumor uptake was 1.2+/-0.24, 0.75+/-0.05, and 0.6+/-0.04 (mean +/- SD) percentage injected dose per gram at 30 min, 1.0 h, and 2.0 h after injection of the radiotracer, respectively. SPECT/CT studies with (111)In-DOTA(GSG)-G3-C12 showed excellent tumor uptake and contrast in the tumor-bearing mice. Specificity of peptide binding was demonstrated by successful blocking (52%) of in vivo tumor uptake of (111)In-DOTA(GSG)-G3-C12 in the presence of its nonradiolabeled counterpart at 2 h after injection. CONCLUSION: This study demonstrated the successful use of a new radiolabeled peptide for the noninvasive imaging of galectin-3-positive breast tumors. This peptide may be a promising candidate for future clinical applications.

The regular and light-dark Suok tests of anxiety and sensorimotor integration: utility for behavioral characterization in laboratory rodents.

Animal behavioral models are crucial for neurobiological research, allowing for the thorough investigation of brain pathogenesis to be performed. In both animals and humans, anxiety has long been linked to vestibular disorders. However, although there are many tests of anxiety and vestibular deficits, there are few protocols that address the interplay between these two domains. The Suok test and its light-dark modification presented here appear to be suitable for testing this pathogenetic link in laboratory rodents. This protocol adds a new dimension to previously used tests by assessing animal anxiety and balancing simultaneously, resulting in efficient, high-throughput screens for testing psychotropic drugs, phenotyping genetically modified animals, and modeling clusters of human disorders related to stress/anxiety and balancing.