Matthew Zeiderman

Targeting Acidity in Pancreatic Adenocarcinoma: Multispectral Optoacoustic Tomography Detects pH-Low Insertion Peptide Probes In Vivo

Background: pH-low insertion peptides (pHLIP) can serve as a targeting moiety that enables pH-sensitive probes to detect solid tumors. Using these probes in conjunction with multispectral optoacoustic tomography (MSOT) is a promising approach to improve imaging for pancreatic cancer. Methods: A pH-sensitive pHLIP (V7) was conjugated to 750 NIR fluorescent dye and evaluated as a targeted probe for pancreatic adenocarcinoma. The pH-insensitive K7 pHLIP served as an untargeted control. Probe binding was assessed in vitro at pH 7.4, 6.8, and 6.6 using human pancreatic cell lines S2VP10 and S2013. Using MSOT, semiquantitative probe accumulation was then assessed in vivo with a murine orthotopic pancreatic adenocarcinoma model. Results: In vitro, the V7-750 probe demonstrated significantly higher fluorescence at pH 6.6 compared with pH 7.4 (S2VP10, P = 0.0119; S2013, P = 0.0160), whereas no difference was observed with the K7-750 control (S2VP10, P = 0.8783; S2013, P = 0.921). In the in vivo S2VP10 model, V7-750 probe resulted in 782.5 MSOT a.u. signal compared with 5.3 MSOT a.u. in K7-750 control in tumor (P = 0.0001). Similarly, V7-750 probe signal was 578.3 MSOT a.u. in the S2013 model compared with K7-750 signal at 5.1 MSOT a.u. (P = 0.0005). There was minimal off-target accumulation of the V7-750 probe within the liver or kidney, and probe distribution was confirmed with ex vivo imaging. Conclusions: Compared with pH-insensitive controls, V7-750 pH-sensitive probe specifically targets pancreatic adenocarcinoma and has minimal off-target accumulation. The noninvasive detection of pH-targeted probes by means of MSOT represents a promising modality to improve the detection and monitoring of pancreatic cancer. Clin Cancer Res; 21(20); 4576–85. ©2015 AACR. See related commentary by Reshetnyak, p. 4502

Acidic pH-Targeted Chitosan-Capped Mesoporous Silica Coated Gold Nanorods Facilitate Detection of Pancreatic Tumors via Multispectral Optoacoustic Tomography

We present a cancer nanomedicine based on acidic pH targeted gold nanorods designed for multispectral optoacoustic tomography (MSOT). We have designed gold nanorods coated with mesoporous silica and subsequently capped with chitosan (CMGs). We have conjugated pH-sensitive variant 7 pHLIP peptide to the CMGs (V7-CMG) to provide targeting specificity to the acidic tumor microenvironment. In vitro, treatment of S2VP10 and MiaPaca2 cells with V7-CMG containing gemcitabine resulted in significantly greater cytotoxicity with 97% and 96.5% cell death, respectively than gemcitabine alone 60% and 76% death at pH 6.5 (S2VP10 pH 6.5 p=0.009; MiaPaca2 pH 6.5 p=0.0197). In vivo, the V7-CMGs provided the contrast and targeting specificity necessary for MSOT of retroperitoneal orthotopic pancreatic tumors. In the in vivo S2VP10 model, the V7-CMG particle preferentially accumulated within the tumor at 17.1 MSOT a.u. signal compared with 0.7 MSOT a.u. in untargeted CMG control in tumor (P = 0.0002). Similarly, V7-CMG signal was 9.34 MSOT a.u. in the S2013 model compared with untargeted CMG signal at 0.15 MSOT a.u. (P = 0.0004). The pH-sensitivity of the targeting pHLIP peptide and chitosan coating makes the particles suitable for simultaneous in vivo tumor imaging and drug delivery.

Abstract 4238: Multispectral optoacoustic tomography detects orthotopic pancreatic tumors in vivo using a nano-contrast agent

There have been very modest developments in pancreatic cancer detection and treatment with mortality essentially remaining unchanged in the last four decades. The major challenge for both early detection and treatment of pancreatic tumors lies in overcoming various biological barriers, especially poor perfusion, insufficient contrast agents/drugs uptake by the tumor, and limitations of traditional imaging modalities. The combination of accurate real-time imaging with tumor-specific nano-contrast agents could mitigate these impediments. We constructed highly stable nano-contrast agents by encapsulating GNRs having aspect ratio 3:1 in PAA (1.5 ± 0.5 nm), and MS (6.25 ± 0.25 nm) shell, respectively and targeted to insulin growth factor 1 receptor (IGF1-R) positive pancreatic tumor cells via Syndecan-1 ligand. IGF1-R specific binding of Syndecan-MS GNRs and Syndecan-PAA-GNR was determined using in an IGF1-R negative cell line (MiaPaca-2) or a blocking antibody to IGF1-R in S2VP10L pancreatic cancer cells determined via flow cytometry. In vivo, mice bearing orthotopic pancreatic tumors were iv injected with 100 nM of Syndecan-MS GNRs and accumulation was determined four hours post injection via Multispectral Optoacoustic Tomography. Biodistribution was determined using a Region of Interest method. The cellular uptake of Syndecan-MS-GNRs significantly enhanced in the S2VP10L cells (503.4 counts) compared to MiaPaca-2 cells (64.1 counts), blocking agent (323.7counts) and untargeted MS GNRs (average 47 counts) revealing that Syndecan-MS-GNRs enhanced both tumor specificity and OA signals by binding with IGF1-R in S2VP10L cells. In vivo, Syndecan-MS-GNRs significantly accumulated in S2VP10L orthotopic pancreatic tumors (233.1 MSOT a.u.) with minimal accumulation in kidney(29.7 MSOT a.u.) and liver (31.4 MSOT a.u.). The Syndecan-MS-GNRs did not accumulate within the orthotopic MiaPaca-2 (IGF1-R negative) mouse model with the biodistribution of pancreas tumor (12.4 MSOT a.u.), kidney (114.3 MSOT a.u.), and liver (35.2 MSOT a.u.). Citation Format: Phillip Chuong, Matthew Zeiderman, William E. Grizzle, Lacey R. McNally. Multispectral optoacoustic tomography detects orthotopic pancreatic tumors in vivo using a nano-contrast agent. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4238.

The Double Opposing Semiocclusive Drain Dressing

Suction drainage with a Jackson-Pratt, Blake, or Hemovac drain is commonly employed for postoperative drainage of a variety of sites including the abdomen, pelvis, cutaneous tissue flaps, and skin grafts.1-3 Some patients may express complaints of discomfort and pain around the skin at the tubes insertion site and/or where it is sutured in place.4 There is no consensus in the literature on the ideal drain dressing; techniques vary and are mainly performed based on surgeon preference or accepted institutional norms. A simple, quick, and inexpensive method for minimizing patient efforts for drain dressing care and potentially, their discomfort, is described. After the suction drain has been placed and secured, two double opposing semiocclusive film dressings are placed around the suction tube at the site of insertion. At our facility, two 6x8 inch Tegaderm (3M, St. Paul, MN, USA) dressings are used. One of these clear semiocclusive dressings is placed on one side of the tube, with half of the dressing in contact with the skin and the other half supporting the tube (Figure 1A). The second is placed on the other side of the tube, directly opposite from the first dressing, again with half of it in contact with the skin, and the other half around the tube (Figure 1B). …

Abstract 5116: Detection of pancreatic cancer using acidic pH targeted probes detected using multispectral optoacoustic tomography

Introduction: The use of theranostic nanoparticles for simultaneous tumor imaging and drug delivery is of great research interest. The tumor extracellular environment is significantly more acidic than physiologic pH, often in the range of pH 6.0-6.8. Exploitation the acidic extracellular tumor environment is a promising method of tumor localization with pH sensitive probes and targets. Further, the use of multispectral optoacoustic tomography (MSOT) allows in vivo 3D tumor imaging via gold nanoparticles or near-infrared dyes conjugated to a targeting molecule. Gemzar is used for first-line treatment of pancreatic adenocarcinoma, a malignancy with less than 5% survival at 5 years. We have created chitosan-capped mesoporous silica gold nanorods (C-MS-GNRs) to serve as pH sensitive theranostic nanoparticles for in vivo tumor imaging and targeted drug delivery. Methods: The chemical nature of all particles were characterized by electron microscopy, UV-Vis, and zeta-potential. Acidic pH specific Gemzar release was measured from C-MS-GNRs by UV-Vis. Cell viability assays on S2VP10 pancreatic adenocarcinoma cells with G-C-MS-GNR and Gemzar alone were performed at pH 6.5 and 7.4. S2VP10 cells were treated in pH 6.5 or 7.4 media with C-MS-GNR loaded with Indocyanin green (ICG) to demonstrate pH-sensitive cell targeting. ICG uptake was read on an Odyssey imaging system. Results: Particle characterization demonstrated appropriate chemical composition. A drug release assay of G-C-MS-GNR demonstrated 1/10 as much drug release at pH7.4 compared to in pH 6.4 or 6.0 media. Cell viability assays demonstrated enhanced cytotoxicity with Gemzar loaded C-MS-GNR at pH 6.5 and 7.4 compared to Gemzar alone. In vitro treatment of S2VP10 cells with C-MS-ICG in pH 6.5 media demonstrated 8X greater ICG delivery by C-MS-ICG than observed at pH 7.4. Conclusions: C-MS-GNR provides an efficacious means of targeting the acidic tumor environment for in vivo tumor imaging and drug delivery. C-MS-GNRs may be a suitable vehicle for tumor-targeted, pH-sensitive drug delivery to this currently untreatable tumor. Citation Format: Matthew Zeiderman, Anil Khanal, Charles W. Kimbrough, Jorge Gomez, William E. Grizzle, Kelly M. McMasters, Lacey R. McNally. Detection of pancreatic cancer using acidic pH targeted probes detected using multispectral optoacoustic tomography. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5116. doi:10.1158/1538-7445.AM2015-5116