Simultaneous Detection of Multiple Tumor-targeted Gold Nanoparticles in HER2-Positive Breast Tumors Using Optoacoustic Imaging

Purpose To develop optoacoustic, spectrally distinct, actively targeted gold nanoparticle-based near-infrared probes (trastuzumab [TRA], TRA-Aurelia-1, and TRA-Aurelia-2) that can be individually identifiable at multispectral optoacoustic tomography (MSOT) of human epidermal growth factor receptor 2 (HER2)-positive breast tumors. Materials and Methods Gold nanoparticle-based near-infrared probes (Aurelia-1 and 2) that are optoacoustically active and spectrally distinct for simultaneous MSOT imaging were synthesized and conjugated to TRA to produce TRA-Aurelia-1 and 2. Freshly resected human HER2-positive (n = 6) and HER2-negative (n = 6) triple-negative breast cancer tumors were treated with TRA-Aurelia-1 and TRA-Aurelia-2 for 2 hours and imaged with MSOT. HER2-expressing DY36T2Q cells and HER2-negative MDA-MB-231 cells were implanted orthotopically into mice (n = 5). MSOT imaging was performed 6 hours following the injection, and the Friedman test was used for analysis. Results TRA-Aurelia-1 (absorption peak, 780 nm) and TRA-Aurelia-2 (absorption peak, 720 nm) were spectrally distinct. HER2-positive human breast tumors exhibited a significant increase in optoacoustic signal following TRA-Aurelia-1 (28.8-fold) or 2 (29.5-fold) (P = .002) treatment relative to HER2-negative tumors. Treatment with TRA-Aurelia-1 and 2 increased optoacoustic signals in DY36T2Q tumors relative to those in MDA-MB-231 controls (14.8-fold, P < .001; 20.8-fold, P < .001, respectively). Conclusion The study demonstrates that TRA-Aurelia 1 and 2 nanoparticles operate as a spectrally distinct HER2 breast tumor-targeted in vivo optoacoustic agent. Keywords: Molecular Imaging, Nanoparticles, Photoacoustic Imaging, Breast Cancer Supplemental material is available for this article. © RSNA, 2023.

Abstract 2458: Comparing influences of active targeting and nanoparticle size on tumor specificity in pancreatic adenocarcinoma

Purpose: While nanoparticles are widely studied as potential theranostic treatments for cancer, weak tumor specificity has hindered clinical translation. Features that contribute to tumor specificity are historically controversial, particularly when using clinically relevant models. Aggressive cancers, such as pancreatic ductal adenocarcinoma (PDAC), stand to benefit from development of highly specific nanoparticles as a theranostic drug delivery system. This work evaluates active targeting and nanoparticle size, in a silica-based nanoparticle for specific accumulation and release of contrast agent within an orthotopically implanted tumor.

Methods: Mesoporous silica nanoparticles (MSNs) were synthesized with wormhole-like pores using a silica precursor to coat a surfactant scaffold. Chitosan was attached to MSN surface as a pH-responsive gatekeeper for encapsulated agents. A series of acidification and basification procedures resulted in loading of photoacoustic contrast agent IR780 within MSN pores. MSNs were further functionalized for attachment of V7 peptide to target aggressive and acidic pancreatic cancer. pH-sensitivity and tumor specificity/uptake was validated using an in vitro PDAC cell model (S2VP10L) prior to implantation and assessment in an animal model. Functionalized MSNs were intravenously injected into athymic mice with orthotopically implanted PDAC tumors. Near infrared fluorescence and optoacoustic imaging were used to evaluate the biodistribution of MSNs subsequent to treatment.

Results: Zeta potential, DLS, and TEM were utilized to show three differently sized MSNs of 26, 45, and 73 nm and confirm conjugation of chitosan and V7 peptide. Dye-release assays indicated significantly increased agent release from MSNs in acidic pH (~90%) compared to biological pH (~15%) (p=0.001). Treatment of PDAC cell line with MSNs showed highest uptake and specificity with actively targeted 26nm particles and that all actively targeted MSNs exhibited greater specificity than all passively targeted MSNs (p&lt;0.05). In vivo results utilizing optoacoustic imaging confirmed that active targeting produces a stronger tumor specificity, and that nanoparticle size has a secondary influence in which the smaller, 26 nm MSNs, showed optimal specificity (p&lt;0.001). Ex vivo evaluation of organs was in agreement with in vivo observations.

Conclusion: Active targeting outperforms nanoparticle size for facilitation of tumor-specific uptake in an acidic PDAC murine model. Active targeting was necessary for high accumulation of MSNs and contrast agent in the tumor. Nanoparticle size had a secondary, but notable influence on tumor uptake in which smaller sized MSNs resulted in higher tumor specificity.

Citation Format: William M. MacCuaig, Abhilash Samykutty, Molly McNally, Ajay Jain, William E. Grizzle, Lacey R. McNally. Comparing influences of active targeting and nanoparticle size on tumor specificity in pancreatic adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2458.

Abstract 300: Matrix metalloproteinase-9 responsive active targeted silica nanoparticles for pancreatic cancer detection by multispectral optoacoustic tomography

Purpose: Pancreatic ductal adenocarcinoma (PDAC) is the most lethal disease and the leading cause of cancer death worldwide. The survival rate of patients with this form of cancer is about 8%. The physiological barrier of the tumor microenvironment composed of a dense stroma and disorganized blood vessels creates a barrier for early identification and treatment of this deadly disease. In recent years, nanoparticle-based controlled delivery systems were developed to exploit the pathophysiology of biological systems such as acidic tumor microenvironment or the altered tumor-specific enzymes to improve the diagnosis and treatment efficacy. Here, we demonstrate the collagenase IV-mediated tumor site-selective release of the IR-780 imaging probe from the M-Ge-SDC1 nanoparticles, revealing the feasibility of the collagenase IV (MMP-9) responsive target specificity for diagnosing pancreatic cancer by multispectral optoacoustic tomography (MSOT) imaging.

Methods: Mesoporous silica nanoparticles (MSN) with wormhole pore topology were synthesized and were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The surface of MSN was conjugated with Gelatin-A to obtain M-Ge. The M-Ge particles were loaded with propidium Iodide (PI) or IR780 infrared imaging dye. The M-Ge surface was further conjugated with Syndecan-1 (SDC1) to improve the target specificity to release imaging cargo from the nanoparticles. Female athymic mice were orthotopically implanted with S2VP10 tumor cells. After a week of tumor implantation, mice were intravenously injected with M-Ge-SDC1 nanoparticles containing IR780 dye and were imaged with MSOT and AMI.

Results: In the current study, Mesoporous silica nanoparticles with 27 nm diameter were synthesized. The Gelatin-A crosslinking on the surface of MSN particles as a gatekeeper was developed that could degrade upon contact with collagenase IV in the tumor microenvironment. The conjugation of SDC1 further improved the tumor specificity. The athymic mice orthotopically implanted with S2VP10 cells closely resemble human PDAC. Our results demonstrated that intravenous delivery of M-Ge-SDC1 nanoparticles could enzymatically degrade (MMP-9) and release IR780 at the tumor site and conjugation of SDC1 further improved the tumor specificity to detect the orthotopically implanted pancreatic tumors (p&lt;0.0001,n=5).

Conclusion: Due to the lack of effective screening tools, PDAC has the lowest survival rate and limited therapeutic efficacy for current FDA-approved drugs compared to other malignancies. Innovative technologies to develop engineered nanoparticles with active targeting moiety and dynamic imaging technology can overcome these limitations. Implementing such systems can enhance PDAC detection that can be translated into the clinic to improve health care.

Citation Format: Abhilash Samykutty, Molly McNally, William M. MacCuaig, Jordan Hagood, Girish Mishra, Barish H. Edil, William E. Grizzle, Lacey R. McNally. Matrix metalloproteinase-9 responsive active targeted silica nanoparticles for pancreatic cancer detection by multispectral optoacoustic tomography [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 300.

Toxicity Assessment of Mesoporous Silica Nanoparticles upon Intravenous Injection in Mice: Implications for Drug Delivery

Nanoparticles are popular tools utilized to selectively deliver drugs and contrast agents for identification and treatment of disease. To determine the usefulness and translational potential of mesoporous silica nanoparticles (MSNs), further evaluations of toxicity are required. MSNs are among the most utilized nano-delivery systems due to ease of synthesis, pore structure, and functionalization. This study aims to elucidate toxicity as a result of intravenous injection of 25 nm MSNs coated with chitosan (C) or polyethylene glycol (PEG) in mice. Following acute and chronic injections, blood was evaluated for standard blood chemistry and complete blood count analyses. Blood chemistry results primarily indicated that no abnormalities were present following acute or chronic injections of MSNs, or C/PEG-coated MSNs. After four weekly administered treatments, vital organs showed minor exacerbation of pre-existing lesions in the 35KPEG-MSN and moderate exacerbation of pre-existing lesions in uncoated MSN and 2KPEG-MSN treatment groups. In contrast, C-MSN treatment groups had minimal changes compared to controls. This study suggests 25 nm MSNs coated with chitosan should elicit minimal toxicity when administered as either single or multiple intravenous injections, but MSNs coated with PEG, especially 2KPEG may exacerbate pre-existing vascular conditions. Further studies should evaluate varying sizes and types of nanoparticles to provide a better overall understanding on the relation between nanoparticles and in vivo toxicity.

Active Targeting Significantly Outperforms Nanoparticle Size in Facilitating Tumor-Specific Uptake in Orthotopic Pancreatic Cancer

Nanoparticles are widely studied as theranostic vehicles for cancer; however, clinical translation has been limited due to poor tumor specificity. Features that maximize tumor uptake remain controversial, particularly when using clinically relevant models. We report a systematic study that assesses two major features for the impact on tumor specificity, i.e., active vs passive targeting and nanoparticle size, to evaluate relative influences in vivo. Active targeting via the V7 peptide is superior to passive targeting for uptake by pancreatic tumors, irrespective of nanoparticle size, observed through in vivo imaging. Size has a secondary effect on uptake for actively targeted nanoparticles in which 26 nm nanoparticles outperform larger 45 and 73 nm nanoparticles. Nanoparticle size had no significant effect on uptake for passively targeted nanoparticles. Results highlight the superiority of active targeting over nanoparticle size for tumor uptake. These findings suggest a framework for optimizing similar nonaggregate nanoparticles for theranostic treatment of recalcitrant cancers.

Antibody drug conjugates in gastrointestinal cancer: From lab to clinical development

The antibody-drug conjugates (ADCs) are one the fastest growing biotherapeutics in oncology and are still in their infancy in gastrointestinal (GI) cancer for clinical applications to improve patient survival. The ADC based approach is developed with tumor specific antigen, antibody carrying cytotoxic agents to precisely target and deliver chemotherapeutics at the tumor site. To date, 11 ADCs have been approved by US-FDA, and more than 80 are in the clinical development phase for different oncological indications. However, The ADCs based therapies in GI cancers are still far from having high-efficient clinical outcomes. The limited success of these ADCs and lessons learned from the past are now being used to develop a newer generation of ADC against GI cancers. In this review, we did a comprehensive assessment of the key components of ADCs, including tumor marker, antibody, cytotoxic payload, and linkage strategy, with a focus on technical improvement and some future trends in the pipeline for clinical translation. The various preclinical and clinical ADCs used in gastrointestinal malignancies, their target, composition and bioconjugation, along with preclinical and clinical outcomes, are discussed. The emphasis is also given to new generation ADCs employing novel mAb, payload, linker, and bioconjugation methods are also included.

Abstract 2790: Evaluation of S100A9 targeted nanoparticles containing rapamycin to treat pancreatic adenocarcinoma

Despite Pancreatic cancer being expected to contribute to only 3% of new cancer cases in both males and females in 2019, it is expected to cause an estimated 45,750 deaths making it the third highest contributor to cancer deaths. This is due to the low survivability associated with pancreatic cancer which has a 5-year survival rate of only 9%. In order to address the poor prognosis common with pancreatic cancer, biomarkers are being used to create therapies targeted to specific cancer cells. The S100A8/A9 complex is a heterodimer, known for modulating the inflammatory response, and it is upregulated in a variety of cancers including pancreatic cancers. For this reason, we selected it as a targeting agent to deliver Rapamycin to pancreatic cancer cells via a mesoporous silica-encased gold nanorod (MS-GNR). The use of this nanoparticle allows an anticancer molecule to be encapsulated within the mesoporous silica matrix by further encapsulation of the nanoparticle with the pH sensitive polymer chitosan. A low pH tumor microenvironment induces relaxation of the chitosan surrounding this chitosan-capped mesoporous silica gold nanorod (CMG) allowing for the anticancer molecule to be released only in cancer cells. The gold nanorod at the core of this enables these nanoparticles to be imaged in real time via Multispectral Optoacoustic Tomography (MSOT). Using these tools, we linked S100A9 to a mesoporous silica-encased gold nanorod which contained Rapamycin held in via the chitosan polymer (S100A9-Rap-CMG). MSOT imaging revealed a strong uptake in S2013Q and MiaPaca pancreatic cancer cells. Further tests showed that at a pH 6.8 S100A9-Rap-CMG treatment resulted in an increase in cell death by 69% compared to treatment at physiologic pH of 7.4 by the S100A9-Rap-CMG's which did not induce cell death. This data indicates the feasibility of S100A9 as a targeting agent for pancreatic cancer cells and the potential benefits of nano-drug delivery of Rapamycin to treat pancreatic adenocarcinoma. The ultimate benefit of the nano-drug delivery includes both increased tumor targeting and mitigating premature drug release and offsite delivery.

Citation Format: Karl Thomas, Molly McNally, Abhilash Samykutty, Lacey R. McNally. Evaluation of S100A9 targeted nanoparticles containing rapamycin to treat pancreatic adenocarcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2790.

Abstract P1-01-04: Uptake of trastuzumab targeted mesoporous silica-coated chitosan capped gold nanorods in breast cancer cell lines and ex vivo patient samples

Background: Approximately two-thirds of operative breast cancer cases are suitable for breast conserving surgery (BCS). In order for BCS to be successful, negative surgical margins should be obtained. Despite improvement in imaging techniques, the ability to achieve negative margins for BCS remains variable with positive margin rates ranging from 21 to 50%. Due to this high re-excision rate, there is an unmet need for a reliable technology to localize the tumor and assess excision margins in real time. Multispectral Optoacoustic Tomography (MSOT) is an emerging imaging modality capable of real time imaging of numerous contrast agents with enhanced spatial resolution of 75µm at depths of 5 cm. This imaging modality has the ability to visualize tumor tissue in a standard operating room setting allowing for precise surgical excision with the potential of increasing rate of negative margins. We developed gold nanorods targeting Human epidermal growth factor receptor-2 (HER2) as a contrast agent to visualize the breast tumor tissue in cell line as well as in ex vivo patient samples using MSOT.

Methods: Gold nanorods were created using hydrogen peroxide (GNR-H2O2) as a reducing agent to create an MSOT detectable contrast agent; the nanorods were stabilized via encapsulation with mesoporous silica together with subsequent chitosan capping. HER2+ breast cancer cells were specifically targeted by conjugating the mesoporous silica-coated chitosan capped gold nanorods (CMGs) to Trastuzumab resulting in TRA-CMG particles. The TRA-CMG particles were evaluated in HER2+ and HER2- breast cancer cell lines as well as fresh HER2+ (N=6) and HER2- freshly resected patient tumor tissues (N=6). All HER2- tumor samples were triple negative breast cancer (TNBC) subtype. Tumor uptake was evaluated in tissue mimicking phantoms using MSOT. In vivo, TRA-CMG were IV injected into female mice with DY36T2Q tumors and imaged using MSOT imaging 6 hours post injection (N=5).

Results: TRA-CMG particles were 8nm wide and 98nm in length. Treatment of HER2+ breast cancer cell lines, DY36T2Q and SKBR3, with TRA-CMG resulted in 2.5x and 3.1x enhanced signal, respectively, as compared to HER2- MDA-MD468 cells (p&lt;0.01). In ex vivo patient samples treated with TRA-CMG that were placed into tissue mimicking phantoms and imaged using MSOT, TRA-CMG had 12x greater uptake in HER2+ samples than in HER2- samples (p&lt;0.004) (Table) In vivo evaluation of TRA-CMG demonstrated tumor specific uptake with 12.1 a.u, compared to liver 1.1 a.u., and kidney 0.9 a.u. in the DY36T2Q breast cancer mode (p&lt;0.007).

Conclusion: The significant uptake of TRA-CMG particles in HER2+ tumors suggests the potential of this particle to be used for diagnostic imaging as well as with intraoperative imaging using MSOT. Future clinical applications include improving the rate of negative margins for patients undergoing breast conservation.

Patient tumor chracteristics and TRC-CMG uptakePatientBreast Cancer SubtypeTumor GradePathologic StageTRA-CMG Uptake (a.u.)1TNBC3ypT3N3a1.22TNBC3ypT2N00.33TNBC3ypT4bN1a0.54ER+PR+HER2+2pT1cN213.35ER+PR-HER2+3pT1cN017.96TNBC2ypT0N00.47ER-PR-HER2+3pT2N019.48ER+PR-HER2+3pT2N015.69ER-PR-HER2+3pT1cN016.610TNBC3pT2N1a0.911ER+PR+HER2+3ypTN018.712TNBC2pT1cN00.7

Citation Format: Akiko Chiba, Alexandra Thomas, Karl N. Thomas, Abhilash Samykutty, Molly McNally, Lacey McNally. Uptake of trastuzumab targeted mesoporous silica-coated chitosan capped gold nanorods in breast cancer cell lines and ex vivo patient samples [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-01-04.

Abstract P3-06-04: Tumor specific cargo release in ex vivo patient samples and murine models of triple negative breast cancer by a pH-targeted nanoparticle: V3-RUBY

Background: Triple negative breast cancer (TNBC), unlike other breast cancer subtypes, lacks a specific targetable receptor. As such tumor specific delivery, which can limit off-target effects of anti-neoplastic therapies, has been an unmet clinical need in treating this aggressive breast cancer subtype. To address this need, we exploited the tumor hallmark of an acidic microenvironment and developed a pH targeted nanoparticle by conjugation of the V3 pH specific peptide on a wormhole pore mesoporous silica nanoparticles (V3-RUBY) and assessed the ability of V3-RUBY to specifically release cargo in ex vivo patient samples and in orthotopically implanted TNBC tumors as detect by multispectral optoacoustic imaging technology (MSOT).

Methods: The silica nanoparticles with wormhole pore architecture were synthesized by sol-gel chemistry and characterized by transmission electron microscopy (TEM), zeta potential, and dynamic light scattering (DLS). The surface base particle was crosslinked with a gatekeeper molecule, chitosan. Further targeting of the particle using V3 pHLIP (low insertion peptide), resulted in the V3-RUBY nanoparticle which allows for pH-sensitive cargo release. The particle was loaded with imaging dye to assess tumor specificity. Fresh ex vivo TNBC patient tumor tissues were resected and rapidly treated with V3-RUBY containing propodium iodide (PI) to evaluate tumor uptake of V3-RUBY and cargo release within the tumor cells, as measured by the red fluorescence of PI when bound to nucleic acids. (PI independently cannot cross cell membranes.) In vivo, female athymic mice were implanted with MDA-MB-468 breast cancer cells by the mammary fat pad injection. Once the tumor reached 3mm in size, athymic mice were intravenously injected with V3-RUBY nanoparticles carrying IR780 infrared imaging dye and were imaged with MSOT inVision 512TF.

Results: The RUBY nanoparticle with wormhole pores was 27 nm diameter. The dual targeting approach of a nanoparticle with V3 targeting peptide and chitosan demonstrated pH specificity around tumor pH. In ex vivo patient TNBC samples, V3-RUBY demonstrated active targeting and dye release at pH 6.8, which approximated the pH measured at surgical tumor removal, in 10 fresh patient samples compared to pH 7.4 controls (p&lt;0.0001, N=10) (Table). There was a non-significant trend towards lower uptake in histological grade 2 tumors, relative to grade 3 tumors. In the murine models, IR780 uptake in the MDA-MB-468 tumors measured 23.2 a.u (arbitrary units) and was 3.1, a.u. in the liver and 0.9 a.u. in the kidneys (p &lt;0.0001, N=5). Tumor accumulation in the MDA-MB-468 model was significantly increased compared to both liver and kidneys (p=0.0002 and p=0.0003).

Conclusion: The tumor-specific release of payload by V3-RUBY suggests the potential of a pH specific target in TNBC, with such a nanoparticle holding promise to deliver both diagnostic and therapeutic cargo directly to the tumor and limit off-target toxicity. Future translation of these technologies could have promise in TNBC, as well as other high-grade breast cancer subtypes and expand treatment options in this challenging area of oncology.

TablePatientBreast Cancer SubtypeTumor GradePathologic StagePI Uptake (a.u.) pH 6.8PI Uptake (a.u.) 7.41TNBC3ypT3N3a33.20.82TNBC3ypT2N038.41.53TNBC3ypT4bN1a36.81.74TNBC3T1bN022.40.85TNBC2T1cN021.80.86TNBC2ypT0N021.50.67TNBC3ypT1aN2a22.00.48TNBC3ypT4dN239.52.19TNBC3T2N2a31.52.210TNBC3T2N1a32.21.8

Citation Format: Alexandra Thomas, Akiko Chiba, Abhilash Samykutty, Molly W. McNally, Lacey R. McNally. Tumor specific cargo release in ex vivo patient samples and murine models of triple negative breast cancer by a pH-targeted nanoparticle: V3-RUBY [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-06-04.

Abstract 1937: pH-responsive tumor-targeted mesoporous silica nanoparticle for the identification of pancreatic cancer using optoacoustic tomography

Purpose: Due to inadequate early detection and inability to operate at advanced stages, pancreatic ductal adenocarcinoma (PDAC) has remained one of the most difficult types of cancer to treat. A small range of non-specific symptoms coupled with quick metastasis rate result in a poor 5-year survival rate; 14% for those diagnosed within stage IA, and as low as 1% for those diagnosed during stage IV. Nanoparticles have recently emerged as a potential delivery agent for diagnostic and therapeutic agents, and although clinical success has not been ample due to targeting accuracy issues. This work shows a nanoparticle that has been functionalized with a pancreatic cancer-specific targeting ligand and exhibits specific particle release in pancreatic malignant environment (pH 6.6) as compared to non-malignant environments (pH 7.4). Methods: Wormhole-pored mesoporous silica nanoparticles were formed at 80°C using Tetrapropyl orthosilicate (TPOS) and a scaffold of hexadecyltrimethyl-ammonium bromide (CTAB). Acetic acid and ethanol were used in dialysis procedures to remove the CTAB scaffold and create worm-like pores. Chitosan was added to coat the silica particles and serve as a gatekeeper. IR-780 was added before the solution was acidified to load the dye into the worm-hole particles created. Shortly after, the solution pH was raised back to physiological levels (pH=7.4) to trap the dye within the particle. The particle surfaces were functionalized to attach a targeting ligand pH-low insertion peptide (V7) to conjugate the dye-loaded nanoparticles. Pancreatic adenocarcinoma cells (S2VP10 line) were plated in pH-7.4,6.8, and 6.6 PBS solutions with the loaded particles to assess uptake via near-infrared fluorescence and multispectral optoacoustic imaging. Results: Zeta potential and dynamic light scattering were used to ensure the 63nm size nanoparticle and proper coating. Near-infrared fluorescence imaging showed ~10X increased signal at pH 6.6 as compared to pH=7.4. MSOT imaging ~5X increased signal in the malignant microenvironment environment that is acidic as compared to the non-malignant environment at pH 7.4. Conclusion: The functionalized wormhole mesoporous silica nanoparticles coated with chitosan demonstrated pH-sensitivity in terms of cellular uptake via NIR fluorescence and MSOT imaging.

Citation Format: William MacCuaig, Abhilash Samykutty, Molly McNally, Kylie Nairon, Surya Banks, William Grizzle, Lacey R. McNally. pH-responsive tumor-targeted mesoporous silica nanoparticle for the identification of pancreatic cancer using optoacoustic tomography [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1937.

Abstract 1952: Tumor microenvironment targeted Rosella nanoparticle for the detection of triple negative breast cancer by multispectral optoacoustic tomography

Purpose: Recent advances in the nanotechnology and molecular imaging provides an excellent opportunity for development of delivery vehicles and imaging probes to improve real-time assessment and early detection of breast cancer progression.The absence of estrogen receptor (ER), progesterone receptor (PR), or HER-2 genes, represents a major clinical challenge for triple negative breast cancer (TNBC). Because of the absence of reliable markers, there is an unmet clinical need for developing efficient methods to identify TNBC. We have developed an acidic pH targeted Rosella nanoparticles that can actively release IR780 dye into orthotopically implanted TNBC tumors to improve tumor detection using multispectral optoacoustic imaging technology (MSOT).

Methods: The Rosella nanoparticles are a mesoporous silica base with wormhole pore architecture containing a chitosan gatekeeper and V3 pHLIP targeting peptide. The particles were synthesized using the sol-gel method and characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The Rosella particles were loaded with propidium Iodide (PI) or IR780 infrared imaging dye to evaluate pH-sensitive cargo release. Female athymic mice were implanted with MDA-MB-468 breast cancer cells by the mammary fat pad injection. Once the tumor reaches 3mm in size, athymic mice were intravenously injected with ROSELLA nanoparticles carrying IR780 dye and were imaged with MSOT.

Results: We have synthesized the Rosella nanoparticle with wormhole pores that is 27 nm diameter and can encapsulate the IR780 imaging probes for the detection of the TNBC. The Rosella particle contains a chitosan gatekeeper which can degrade upon contact with acidic pH tumor to prevent off-target release and is further sensitized to pH using V3 peptide. The Rosella nanoparticles can detect acidic tumor microenvironment and can penetrate inside the tumor cells. As a model of TNBC, we have injected MDA-MB-468 cells into the mammary fat pad of the female athymic mice to develop breast tumors. Once the tumor reached 3mm in size, we have intravenously delivered ROSELLA nanoparticles to the athymic mice with TNBC tumors. Our results were demonstrated that the intravenous injection of the ROSELLA particles could detect the orthotopically implanted TNBC tumors (p&lt;0.0001,n=5).

Conclusion: most aggressive subtypes of breast cancer, TNBC has a poor response for majority of the FDA-approved breast cancer drugs. To overcome these limitations, the distinct nanoformulations with potent imaging technology will enable to develop tumor-penetrating nanoparticles to more effectively deliver chemotherapeutics or imaging agents with least off-target effects. Future translation of these technologies has a high clinical impact concerning our current treatment options for TNBC patients.

Citation Format: Abhilash Samykutty, Molly McNally, Alexandra Thomas, William Grizzle, Lacey R. McNally. Tumor microenvironment targeted Rosella nanoparticle for the detection of triple negative breast cancer by multispectral optoacoustic tomography [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1952.

Abstract 1954: Tracking of orally-administered particles within the gastrointestinal tract of murine models using multispectral optoacoustic tomography

While particle carriers have potential to revolutionize disease treatment, using these carriers requires knowledge of spatial and temporal biodistribution. The goal of this study was to track orally administered particle uptake and trafficking through the murine gastrointestinal (GI) tract using multispectral optoacoustic tomography (MSOT).

Polylactic acid (PLA) particles encapsulating AlexaFluor 680 (AF680) dye conjugated to bovine serum albumin (BSA) were orally gavaged into mice. Particle uptake and trafficking were observed using MSOT imaging with subsequent confirmation of particle uptake via fluorescent microscopy. Mice treated with PLA-AF680-BSA particles exhibited MSOT signal within the small bowel wall at 1 and 6 h, colon wall at 6, 12, and 24 h, and mesenteric lymph node 24 and 48h. Particle localization identified using MSOT correlated with fluorescence microscopy. Despite the potential of GI tract motion artifacts, MSOT allowed for teal-time tracking of particles within the GI tract in a non-invasive and real-time manner.

Future use of MSOT in conjunction with particles containing both protein-conjugated fluorophores as well as therapeutic agents could allow for non-invasive, real time tracking of particle uptake and drug delivery.

Citation Format: Neal Bhutiani, Abhilash Samykutty, Kelly McMasters, Nejat Egilmez, Lacey R. McNally. Tracking of orally-administered particles within the gastrointestinal tract of murine models using multispectral optoacoustic tomography [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1954.

Abstract 1934: Development of spectrally distinct silica coated gold nanorods for detection of cancer using MSOT

Traditional cancer imaging devices are limited in their ability to screen for multiple contrast agents simultaneously in real time. Multispectral Optoacoustic Tomography (MSOT) is an emerging imaging modality capable of real-time imaging of numerous contrast agents with enhanced spatial resolution of 75µm at depths of 5 cm. The use of exogenous contrast agents in MSOT remains largely unexplored, so we developed two species of spectrally distinct gold nanorod as contrast agents for use in MSOT. Our goal was to evaluate the potential of MSOT to spectrally differentiate two exogenous contrast agents simultaneously. Two gold nanorod species were created using hydrogen peroxide (GNR-H2O2) or ascorbic (GNR-ASC) acid as reducing agents to modify the length of each species to create nanorods with individual light absorbance spectra in the IR range (680-900 nm). These gold nanorods were highly stabilized via encapsulation with mesoporous silica along with a subsequent chitosan capping. Human epidermal growth factor receptor 2 positive (HER2+) cells were specifically targeted by conjugating these mesoporous silica-coated chitosan capped gold nanorods (CMGs) to Trastuzumab resulting in TRA-CMG particles. Both TRA-CMG-ASC and TRA-CMG-H2O2 resulted in optoacoustic spectrally distinct signals when imaged in tissue phantoms both individually as well as mixed within the same well after multispectral processing using linear regression. Treatment of HER2+ breast cancer cell lines, DY36T2Q and SKBR3, with TRA-CMG-H2O2 resulted in 2.5x and 3.1x enhanced signal, respectively, as compared to HER2- MDA-MD468 cells. Treatment of DY36T2Q and SKBR3 cells with TRA-CMG-ASC demonstrated 3.7x and 6.9x, respectively, compared to MDA-MD468. In all three cell lines treated with a combination of TRA-CMG-H2O2’s and TRA-CMG-ASC’s clear and distinct signals were observed for each particle, demonstrating that each TRA-CMG possessed and maintained a detectibly distinct optoacoustic spectrum, in the IR range, allowing them to be detectable as separate contrast agents in MSOT while proximate to other targeted contrast agents. Both particles have demonstrated that they can be simultaneously administered and targeted at HER2+ cell while also maintaining distinct photoacoustic signals in MSOT upon consolidation. Each particle species, targeted to the same cells, were capable of being monitored individually in the presence of the other gold nanorod contrast agent.

Citation Format: Karl N. Thomas, Abhilash Samykutty, Molly McNally, Lacey R. McNally. Development of spectrally distinct silica coated gold nanorods for detection of cancer using MSOT [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1934.

In vivo tracking of orally-administered particles within the gastrointestinal tract of murine models using multispectral optoacoustic tomography

While particle carriers have potential to revolutionize disease treatment, using these carriers requires knowledge of spatial and temporal biodistribution. The goal of this study was to track orally administered particle uptake and trafficking through the murine gastrointestinal (GI) tract using multispectral optoacoustic tomography (MSOT). Polylactic acid (PLA) particles encapsulating AlexaFluor 680 (AF680) dye conjugated to bovine serum albumin (BSA) were orally gavaged into mice. Particle uptake and trafficking were observed using MSOT imaging with subsequent confirmation of particle uptake via fluorescent microscopy. Mice treated with PLA-AF680-BSA particles exhibited MSOT signal within the small bowel wall at 1 and 6 h, colon wall at 6, 12, and 24 h, and mesenteric lymph node 24 and 48 h. Particle localization identified using MSOT correlated with fluorescence microscopy. Despite the potential of GI tract motion artifacts, MSOT allowed for teal-time tracking of particles within the GI tract in a non-invasive and real-time manner. Future use of MSOT in conjunction with particles containing both protein-conjugated fluorophores as well as therapeutic agents could allow for non-invasive, real time tracking of particle uptake and drug delivery.

Optoacoustic imaging identifies ovarian cancer using a microenvironment targeted theranostic wormhole mesoporous silica nanoparticle

At the intersection of the newly emerging fields of optoacoustic imaging and theranostic nanomedicine, promising clinical progress can be made in dismal prognosis of ovarian cancer. An acidic pH targeted wormhole mesoporous silica nanoparticle (V7-RUBY) was developed to serve as a novel tumor specific theranostic nanoparticle detectable using multispectral optoacoustic tomographic (MSOT) imaging. We report the synthesis of a small, < 40 nm, biocompatible asymmetric wormhole pore mesoporous silica core particle that has both large loading capacity and favorable release kinetics combined with tumor-specific targeting and gatekeeping. V7-RUBY exploits the acidic tumor microenvironment for tumor-specific targeting and tumor-specific release. In vitro, treatment with V7-RUBY containing either paclitaxel or carboplatin resulted in increased cell death at pH 6.6 in comparison to drug alone (p < 0.0001). In orthotopic ovarian xenograft mouse models, V7-RUBY containing IR780 was specifically detected within the tumor 7X and 4X higher than the liver and >10X higher than in the kidney using both multispectral optoacoustic tomography (MSOT) imaging with secondary confirmation using near infrared fluorescence imaging (p < 0.0004). The V7-RUBY system carrying a cargo of either contrast agent or an anti-neoplastic drug has the potential to become a theranostic nanoparticle which can improve both diagnosis and treatment of ovarian cancer.

Osteopontin-targeted probe detects orthotopic breast cancers using optoacoustic imaging

Improved detection of breast cancer using highly sensitive, tumor-specific imaging would facilitate diagnosis, surveillance and assessment of response to treatment. We conjugated osteopontin peptide to an infrared fluorescent dye to serve as a contrast agent for detection of breast cancer by multispectral optoacoustic tomography (MSOT). Selective binding of the osteopontin-based probe was identified using flow cytometry and near infrared fluorescent imaging in triple negative and HER2 positive breast cancer cell lines in vitro. Osteopontin-750 accumulation was evaluated in vivo using MSOT with secondary confirmation of signal accumulation using near infrared fluorescent imaging. The osteopontin-based probe demonstrated binding to breast cancer cells in vitro. Similarly, after intravenous administration of the osteopontin-750 probe, it accumulated preferentially in the subcutaneous breast tumor in nude mice (557 MSOT a.u. compared to untargeted organs such as kidney (53.7 MSOT a.u.) and liver (32.1 MSOT a.u.). At 2.5 h post-injection, signal intensity within the tumor was 9.7 and 17 times greater in the tumor bed than in the kidney or liver, respectively. Fluorescence imaging ex vivo comparing tumor signal to that of nontarget organs confirmed the results in vivo. MSOT imaging demonstrated selective accumulation of the fluorescent osteopontin targeting probe to tumor sites both in vitro and in vivo, and provided high-resolution images. Further development of this tool is promising for advanced diagnostic imaging, disease surveillance and therapeutic models that limit nontarget toxicity.

Applying dynamic contrast enhanced MSOT imaging to intratumoral pharmacokinetic modeling

Examining the dynamics of an agent in the tumor microenvironment can offer critical insights to the influx rate and accumulation of the agent. Intratumoral kinetic characterization in the in vivo setting can further elicudate distribution patterns and tumor microenvironment. Dynamic contrast-enhanced Multispectral Optoacoustic Tomographic imaging (DCE-MSOT) acquires serial MSOT images with the administration of an exogenous contrast agent over time. We tracked the dynamics of a tumor-targeted contrast agent, HypoxiSense 680 (HS680), in breast xenograft mouse models using MSOT. Arterial input function (AIF) approach with MSOT imaging allowed for tracking HS680 dynamics within the mouse. The optoacoustic signal for HS680 was quantified using the ROI function in the ViewMSOT software. A two-compartment pharmacokinetics (PK) model constructed in MATLAB to fit rate parameters. The contrast influx (k_in) and outflux (k_out) rate constants predicted are k_in = 1.96 × 10^-2 s^-1 and k_out = 9.5 × 10^-3 s^-1 (R = 0.9945).

Abstract 4103: Utility of multispectral optoacoustic tomography in imaging pancreatic tumors using a uPA-probe

Background: Pancreatic cancer has the lowest 5-year survival rate of all cancer types. Current methods of pancreatic cancer screening, diagnosis and treatment have failed to improve outcome in the last few decades. Potential explanation for this failure may be explained by the hypovascularized nature of pancreatic cancer, making conventional chemotherapy and imaging modality suboptimal. There is a potential for improved imaging using a new imaging modality, multispectral optoacoustic tomography (MSOT). We hypothesize that a using urokinase plasminogen activator (uPA) contrast agent while using MSOT imaging would improve identification of orthotopic pancreatic cancer in xenografts. Methods: Expression of uPA receptor (uPAR) were evaluated in pancreatic tumor cell lines, Panc1, S2CP9, MiaPaca-2 and S2VP10 using western blot. A uPA targeted contrast agent was created using standard bioconjugation methods with the Hilite 750 near infrared (NIR) dye. Five SCID mice were orthotopically implanted with S2CP9 (1.5 x 105) and 5 additional SCID mice were implanted with MiaPaCa2 (2.0 x 106) pancreatic tumor cells. When tumor size reached 3mm, 200µL of 100 nM uPA-750 probe or 750 dye alone was injected into mice. Biodistribution and accumulation of the uPA-750 probe was visualized using MSOT imaged at 2-hour intervals for 8 hours and at 24 hours. Accumulation of uPA-750 probe was evaluated in the tumor, liver, and kidney using NIR fluorescent imaging. Results: All pancreatic cancer cell line expressed uPAR with the highest in S2CP9 cells (3.0x), S2VP10 (2.5x), Panc1 (1.77x) and MiaPaca-2 (1.3x). In vivo, peak intensity of uPA-750 probe was successfully detected using MSOT at 4 hours, within the pancreas tumor in slices from 37mm-41mm. uPA-750 probe was undetectable within the tumor after 8 hours. Using ex vivo NIR fluorescence imaging, uPA-probe signal was detected only within the pancreatic tumor, however, no signal was detected in the liver or kidney. Conclusion: This study demonstrated MSOT imaging using uPA-probe as a contract agent may lead to improved pancreatic cancer detection which may lead to improvement in overall outcome.

Citation Format: Akiko Chiba, Abhilash Samykutty, Mary Smith, Lacey McNally. Utility of multispectral optoacoustic tomography in imaging pancreatic tumors using a uPA-probe [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4103.

Abstract 4122: Acidic tumor microenvironment targeted wormhole-shaped mesoporous silica nanoparticles to detect ovarian cancer by multispectral optoacoustic tomography

Purpose: The implementation of the innovative technologies remains the top priority for the development of potential modalities for the diagnosis and treatment of various cancers. Despite all the recent advances, ovarian cancer is considered as a lethal gynecologic malignancy in which vast majority of the cases are diagnosed at the late metastatic stage at which the prognosis is poor. Because of the few apparent early symptoms, significant effort was made for developing efficient methods to identify early progression of the disease. We demonstrated that the bioconjugation of the V7 peptide on 27nm wormhole mesoporous silica nanoparticles (V7-CWMSN) particles specifically release the IR780 imaging probe at the orthotopically implanted early-stage ovarian tumor to detect by multispectral optoacoustic imaging technology (MSOT).

Methods: Wormhole mesoporous silica nanoparticles (WMSN) were synthesized by sol-gel chemistry. The WMSN were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The surface of the WMSN particle was functionalized with pH sensitizer chitosan to obtain CWMSN. The CWMSN particle was loaded with propidium Iodide (PI) or IR780 infrared imaging dye. Further, the conjugation of the CWMSN with V7 pHLIP peptide (V7-CWMSN) developed pH sensitive cargo release from the nanoparticles. Female athymic mice were orthotopically implanted with ES-2 ovarian cancer cells. Following 10 days of orthotopic implantation of the tumor cells, mice were intravenously injected with V7-CWMSN particles containing IR780 dye and were imaged with MSOT.

Results: In the current study, we have synthesized the wormhole-shaped mesoporous silica particles (WMSN) with the 27 nm diameter carrying IR780 imaging probes for the detection of early-stage ovarian cancer. The V7 peptide undergoes a conformational change upon contact with the acidic tumor microenvironment. Also, the chitosan crosslinking on the surface of the particles (V7-CWMSN) acts as a gatekeeper that is degradable upon contact with acidic pH tumor to prevent off-target release. As a model for ovarian cancer, we have used athymic mice orthotopically implanted with ovarian cancer cells. This model closely resembles the human ovarian cancer pathophysiology. Our results have demonstrated that the intravenous delivery of V7-CWMSN particles could detect the orthotopically implanted early-stage ovarian tumors (p&lt;0.0001,n=5).

Conclusion: The development of the distinct nanoformulations with potent imaging technology enables the visualization of early-stage ovarian tumors. Translating these modalities may allow clinicians to identify early-stage malignancies that are currently undetectable through conventional imaging techniques.

Citation Format: Abhilash Samykutty, Molly W. McNally, William E. Grizzle, Akiko Chiba, Alexandra Thomas, Lacey R. McNally. Acidic tumor microenvironment targeted wormhole-shaped mesoporous silica nanoparticles to detect ovarian cancer by multispectral optoacoustic tomography [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4122.

Abstract 4269: Dynamic contrast-enhanced MSOT imaging to intratumoral pharmacokinetic modeling

Introduction: Interactions between biological features and nanoparticles could affect tracer biodistribution, kinetics, clearance, and translocation. Because these effects cannot be simply extrapolated from in vitro studies, in vivo quantitative data are needed to determine the pharmacokinetic properties of tracers. Planar fluorescence or 2D fluorescent /bioluminescence imaging has the potential for the tracers to accumulate outside of the tumor and the potential of light scattering. MSOT allows for more precise determination of signal origin and intensity. HypoxiSense 680 is a tracer that targets the hypoxic tumor environment. Our objective is to assess the pharmacokinetics of HypoxiSense 680 in the context of an orthotopic breast tumor in vivo using MSOT. This study takes advantage of a novel contrast tracking imaging modality to study intratumoral pharmacokinetics in in vivo setting with a hypoxia-targeting tracer. Methods: Female, athymic mice were orthotopically implanted with MDA-MB-231 cells and tumors were allowed to grow to 4mm in diameter prior to the evaluation of the tracer. Mice were anesthetized with isoflurane and a mixture of 0.1L of O2 and 0.9L of medical air prior to the insertion of a tail vein catheter. The mouse was placed into the MSOT scanner for 10 minutes to equilibrate. Once the breast tumor was localized, images were acquired for 5 minutes to obtain a baseline measurement. Subsequently, 100μL of HypoxiSense 680 at the recommended dosage of 2nmol per mouse was injected over the course of 30s followed by a catheter flush with 100μL of saline solution. MSOT inVision 256-TF continuously measured optoacoustic signal within the mouse in vivo for a duration of 25 minutes. HypoxiSense 680 signal was isolated by spectral unmixing using backprojection algorithm. Results: A 2-compartmental PK model was constructed in MATLAB and curve-fitted against the animal data. There were two compartments to account for the contrast within the circulatory system and the tumor microenvironment. Rate constants of the model were determined by fitting the model curve to the experimental MSOT imaging data: kforward=2.76x10-4 sec-1, kreverse=4.73x10-4 sec-1, kelcentral=1.01x10-5 sec-1, kelperipheral=3.18x10-7 sec-1. The goodness of fit was evaluated (R=0.83, RMSE=0.0015). Conclusion: Optoacoustic imaging with MSOT provides live tracking of spectrally unique contrasts in vivo. This capability allows for a novel characterization method of intratumoral drug/contrast kinetics in vivo in mouse tumor models.

Citation Format: Ted G. Xiao, Abhilash Samykutty, Jared Weis, Scott Gayzik, Umit Topaloglu, Alexandra Thomas, Akiko Chiba, Lacey R. McNally. Dynamic contrast-enhanced MSOT imaging to intratumoral pharmacokinetic modeling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4269.

Abstract 4664: Enzymatically-responsive tumor-targeted mesoporous silica nanoparticle for identification of pancreatic cancer

Purpose: Pancreatic cancer remains an unsolved health issue, with its rapid progression and resistance to modern therapy leading to poor prognoses for most patients. The prevalence of metastasis in pancreatic cancer makes complete tumor location and removal rare, and those who do have resectable disease have only a 20% 5-year survival rate. In recent years, nanoparticles have been explored as targeted delivery agents for chemotherapeutic drugs and imaging dyes, however few have achieved clinical success due to overestimation of biological phenomena and reliance on passive targeting systems. In this work, an enzyme-responsive nanoparticle has been developed for increased active pancreatic tumor targeting and specific release at biologically-significant enzyme concentrations.

Methods: Mesoporous silica nanoparticles were formed using a scaffold of hexadecyltrimethylammonium bromide (CTAB) at 80°C. The scaffold was removed to form wormhole-like pores using a series of dialysis procedures. Transmission electron microscopy (TEM) confirmed the 35 nm diameter and porous structure of the particles. The particles were then loaded with IR780 dye, and surfaces were functionalized with (3-aminopropyl) triethoxysilane (APTES). The loaded particles were then encapsulated with a combination of Type A and Type B gelatin, followed by a stabilizing polyvinylpyrrolidone (PVP) layer. Dynamic light scattering (DLS) and zeta potential were used to confirm coating. Coated particle samples were exposed to collagenase type IV (MMP-9) enzyme to test encapsulation efficiency and enzyme sensitivity. Enzyme-treated and intact samples were transferred to tissue phantoms, and Multispectral optoacoustic tomography (MSOT) was used for comparative analysis.

Results: TEM confirmed the formation of stable 35 nm silica nanoparticles with a wormhole-like pore structure. Zeta potential decrease from 55 mV to 5 mV and DLS particle diameter increase from 35 nm to 334.5 nm indicated binding of gelatin and PVP to particle surfaces. MSOT imaging showed 10 X increased signals from untreated nanoparticles as compared to enzyme-treated nanoparticles, indicating that dye molecules remained inside the pores of coated particles and were released when exposed to MMP-9.

Conclusion: Gelatin/PVP-coated mesoporous silica nanoparticles encapsulated dye and demonstrated MMP-9 activated dye release at biologically-relevant enzyme concentrations.

Citation Format: Kylie Nairon, Abhilash Samykutty, Molly W. McNally, Girish Mishra, William E. Grizzle, Lacey R. McNally. Enzymatically-responsive tumor-targeted mesoporous silica nanoparticle for identification of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4664.

Abstract 3727: Dual acidic pH targeted mesoporous silica nanoparticles for noninvasive detection of triple negative breast cancer

Purpose: Current screening methods for triple negative breast cancer suggest the presence and size of tumor, but do not identify the tumor microenvironment. The inability to determine precise tumor location and position following diagnosis impedes medical confidence in surgical resection and radiation therapy. Theranostic nanoparticles can be targeted for dye and drug delivery to facilitate non-invasive characterization and treatment of malignancies. Combinational use of nanomedicine and Multispectral Optoacoustic Tomography (MSOT) renders high resolution images through ultrasonic detection of thermoelastic dye expansion (the optoacoustic effect). Approaches in nanomedicine are steadily growing, but clinical evaluation relies on minimizing off-target accumulation and controlling cargo release. We evaluated a mesoporous silica nanoparticles with pH-sensitive chitosan gatekeeper and tumor targeting V3 pH low-insertion peptide (V3 pHLIP) conjugation (V3-CMSN-780) for dual acidic pH targeted delivery to triple negative breast cancer. Methods: Mesoporous silica nanoparticles were synthesized around a structural skeleton of hexadecyltrimethylammonium bromide (CTAB). CTAB was removed from the particles through repeated dialysis. Subsequent particles were characterized with digital light scattering (DLS) and zetasizer to confirm particle size and zeta potential. Mesoporous nanoparticles were then coated with chitosan for extracellular acidic pH selectivity and functionalized with variant 3 pH low-insertion peptide (V3 pHLIP) to promote anchoring of the particle to tumor cells. Functionalized nanoparticles (V3-CMSN) were loaded with NIR 780 (5 mg/mL) and delivered to MDA-MB-231 and MDA-MB-468 malignant cell lines at pH 7.4, 6.8, and 6.6 to confirm pH-sensitive dye release into the cells with Near Infrared fluorescent imaging. V3-CMSN treated cells were inserted into tissue mimicking phantoms which were evaluated using MSOT. Results: The size of V3-CMSN-780 was 35 d. nm with a zeta potential of 25 mV. V3-CMSN were loaded with 780 dye with a dye loading efficiency of 77%. Cellular uptake of V3-CMSN-780 within MDA-MB-231 cells was 2152 a.u., 5242 a.u., and 3639 a.u. at pHs 7.4, 6.8, and 6.6, respectively, based NIR fluorescent imaging. Treatment of MDA-MB-231 cells with V3-CMSN-780 within tissue mimicking phantoms also confirmed acidic pH selectivity of the particles with a 6X and 4X accumulation of particles at pH 6.8 and 6.6 as compared to pH 7.4. While similar results were observed in MDA-MB-468 cells with NIR fluorescent imaging, MSOT imaging indicated that MDA-MB-468 cells treated at pH 6.8 and 6.6 had increased 780 signal, 110X and 16X, incomparison to pH 7.4. Conclusion: Successful dual targeting of breast tumor cells provides a foundation for later in vivo and ex vivo studies using V3-780-CMSNs to deliver diagnostic and therapeutic cargo to malignant breast tissue.

Citation Format: Joshua T. Hayes, Abhilash Samykutty, Molly McNally, Alexandra Thomas, Akiko Chiba, William Grizzle, Karen M. Winkfield, Lacey R. McNally. Dual acidic pH targeted mesoporous silica nanoparticles for noninvasive detection of triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3727.

Isolation, identification, and characterization of novel nanovesicles

Extracellular microvesicles (EVs) have been recognized for many potential clinical applications including biomarkers for disease diagnosis. In this study, we identified a major population of EVs by simply screening fluid samples with a nanosizer. Unlike other EVs, this extracellular nanovesicle (named HG-NV, HG-NV stands for HomoGenous nanovesicle as well as for Huang-Ge- nanovesicle) can be detected with a nanosizer with minimal in vitro manipulation and are much more homogenous in size (8–12 nm) than other EVs. A simple filtration platform is capable of separating HG-NVs from peripheral blood or cell culture supernatants. In comparison with corresponding exosome profiles, HG-NVs released from both mouse and human breast tumor cells are enriched with RNAs. Tumor derived HG-NVs are more potent in promoting tumor progression than exosomes. In summary, we identified a major subset of EVs as a previously unrecognized nanovesicle. Tumor cell derived HG-NVs promote tumor progression. Molecules predominantly present in breast tumor HG-NVs have been identified and characterized. This discovery may have implications in advancing both microvesicle biology research and clinical management including potential used as a biomarker.

Grapefruit-derived nanovectors deliver miR-18a for treatment of liver metastasis of colon cancer by induction of M1 macrophages

Liver metastasis accounts for many of the cancer deaths in patients. Effective treatment for metastatic liver tumors is not available. Here, we provide evidence for the role of miR-18a in the induction of liver M1 (F4/80⁺interferon gamma (IFNγ)⁺IL-12⁺) macrophages. We found that miR-18a encapsulated in grapefruit-derived nanovector (GNV) mediated inhibition of liver metastasis that is dependent upon the induction of M1 (F4/80⁺IFNγ⁺IL-12⁺) macrophages; depletion of macrophages eliminated its anti-metastasis effect. Furthermore, the miR-18a mediated induction of macrophage IFNγ by targeting IRF2 is required for subsequent induction of IL-12. IL-12 then activates natural killer (NK) and natural killer T (NKT) cells for inhibition of liver metastasis of colon cancer. This conclusion is supported by the fact that knockout of IFNγ eliminates miR-18a mediated induction of IL-12, miR-18a treatment has an anti-metastatic effects in T cell deficient mice but there is no anti-metastatic effect on NK and NKT deficient mice. Co-delivery of miR-18a and siRNA IL-12 to macrophages did not result in activation of co-cultured NK and NKT cells. Taken together our results indicate that miR-18a can act as an inhibitor for liver metastasis through induction of M1 macrophages.

Broccoli-derived nanoparticle inhibits mouse colitis by activating dendritic cell AMP-activated protein kinase

The intestinal immune system is continuously exposed to massive amounts of nanoparticles derived from food. Whether nanoparticles from plants we eat daily have a role in maintaining intestinal immune homeostasis is poorly defined. Here, we present evidence supporting our hypothesis that edible nanoparticles regulate intestinal immune homeostasis by targeting DC cell. With three mouse colitis models, our data show that orally given nanoparticles isolated from broccoli extracts protect mice against colitis. Broccoli-derived nanoparticles (BDN) mediated activation of adenosine monophosphate-activated protein kinase (AMPK) in dendritic cell (DC) plays a role in not only prevention of DC activation but also induction of tolerant DCs. Adoptively transferring DCs pre-pulsed with total BDN lipids but not sulforaphane depleted BDN lipids prevented DSS induced colitis in B6 mice, supporting the role of BDN sulforaphane in the induction of DC tolerance. Adoptively transferring AMPK+/+ but not AMPK−/− DCs pre-pulsed with sulforaphane prevented DSS induced colitis in B6 mice, further supporting the DC AMPK role in sulforaphane mediated prevention of DSS induced colitis. This finding could open new preventive/therapeutic avenues to address intestinal related inflammatory diseases via activating AMPK.

Broccoli-Derived Nanoparticle Inhibits Mouse Colitis by Activating Dendritic Cell AMP-Activated Protein Kinase

The intestinal immune system is continuously exposed to massive amounts of nanoparticles derived from food. Whether nanoparticles from plants we eat daily have a role in maintaining intestinal immune homeostasis is poorly defined. Here, we present evidence supporting our hypothesis that edible nanoparticles regulate intestinal immune homeostasis by targeting dendritic cells (DCs). Using three mouse colitis models, our data show that orally given nanoparticles isolated from broccoli extracts protect mice against colitis. Broccoli-derived nanoparticle (BDN)-mediated activation of adenosine monophosphate-activated protein kinase (AMPK) in DCs plays a role in not only prevention of DC activation but also induction of tolerant DCs. Adoptively transferring DCs pre-pulsed with total BDN lipids, but not sulforaphane (SFN)-depleted BDN lipids, prevented DSS-induced colitis in C57BL/6 (B6) mice, supporting the role of BDN SFN in the induction of DC tolerance. Adoptively transferring AMPK^+/+, but not AMPK^-/-, DCs pre-pulsed with SFN prevented DSS-induced colitis in B6 mice, further supporting the DC AMPK role in SFN-mediated prevention of DSS-induced colitis. This finding could open new preventive or therapeutic avenues to address intestinal-related inflammatory diseases via activating AMPK.

MVP-mediated exosomal sorting of miR-193a promotes colon cancer progression

Exosomes are emerging mediators of intercellular communication; whether the release of exosomes has an effect on the exosome donor cells in addition to the recipient cells has not been investigated to any extent. Here, we examine different exosomal miRNA expression profiles in primary mouse colon tumour, liver metastasis of colon cancer and naive colon tissues. In more advanced disease, higher levels of tumour suppressor miRNAs are encapsulated in the exosomes. miR-193a interacts with major vault protein (MVP). Knockout of MVP leads to miR-193a accumulation in the exosomal donor cells instead of exosomes, inhibiting tumour progression. Furthermore, miR-193a causes cell cycle G1 arrest and cell proliferation repression through targeting of Caprin1, which upregulates Ccnd2 and c-Myc. Human colon cancer patients with more advanced disease show higher levels of circulating exosomal miR-193a. In summary, our data demonstrate that MVP-mediated selective sorting of tumour suppressor miRNA into exosomes promotes tumour progression.

Exosomes are involved in the development of metastasis but how their composition is regulated is not well known. Here the authors propose that major vault protein-dependent loading of miR-193a into exosomes could be a general mechanism by which cancer cells get rid of oncosuppressor miRNAs.

Grapefruit-derived Nanovectors Delivering Therapeutic miR17 Through an Intranasal Route Inhibit Brain Tumor Progression

The lack of access to the brain is a major obstacle for central nervous system drug development. In this study, we demonstrate the capability of a grapefruit-derived nanovector (GNV) to carry miR17 for therapeutic treatment of mouse brain tumor. We show that GNVs coated with folic acid (FA-GNVs) are enhanced for targeting the GNVs to a folate receptor-positive GL-26 brain tumor. Additionally, FA-GNV-coated polyethylenimine (FA-pGNVs) not only enhance the capacity to carry RNA, but the toxicity of the polyethylenimine is eliminated by the GNVs. Intranasal administration of miR17 carried by FA-pGNVs led to rapid delivery of miR17 to the brain that was selectively taken up by GL-26 tumor cells. Mice treated intranasally with FA-pGNV/miR17 had delayed brain tumor growth. Our results demonstrate that this strategy may provide a noninvasive therapeutic approach for treating brain-related disease through intranasal delivery.

Grapefruit-derived Nanovectors Delivering Therapeutic miR17 Through an Intranasal Route Inhibit Brain Tumor Progression

The lack of access to the brain is a major obstacle for central nervous system drug development. In this study, we demonstrate the capability of a grapefruit-derived nanovector (GNV) to carry miR17 for therapeutic treatment of mouse brain tumor. We show that GNVs coated with folic acid (FA-GNVs) are enhanced for targeting the GNVs to a folate receptor-positive GL-26 brain tumor. Additionally, FA-GNV-coated polyethylenimine (FA-pGNVs) not only enhance the capacity to carry RNA, but the toxicity of the polyethylenimine is eliminated by the GNVs. Intranasal administration of miR17 carried by FA-pGNVs led to rapid delivery of miR17 to the brain that was selectively taken up by GL-26 tumor cells. Mice treated intranasally with FA-pGNV/miR17 had delayed brain tumor growth. Our results demonstrate that this strategy may provide a noninvasive therapeutic approach for treating brain-related disease through intranasal delivery.

Curcumin inhibits PhIP induced cytotoxicity in breast epithelial cells through multiple molecular targets

Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), found in cooked meat, is a known food carcinogen that causes several types of cancer, including breast cancer, as PhIP metabolites produce DNA adduct and DNA strand breaks. Curcumin, obtained from the rhizome of Curcuma longa, has potent anticancer activity. To date, no study has examined the interaction of PhIP with curcumin in breast epithelial cells. The present study demonstrates the mechanisms by which curcumin inhibits PhIP-induced cytotoxicity in normal breast epithelial cells (MCF-10A). Curcumin significantly inhibited PhIP-induced DNA adduct formation and DNA double stand breaks with a concomitant decrease in reactive oxygen species (ROS) production. The expression of Nrf2, FOXO targets; DNA repair genes BRCA-1, H2AFX and PARP-1; and tumor suppressor P16 was studied to evaluate the influence on these core signaling pathways. PhIP induced the expression of various antioxidant and DNA repair genes. However, co-treatment with curcumin inhibited this expression. PhIP suppressed the expression of the tumor suppressor P16 gene, whereas curcumin co-treatment increased its expression. Caspase-3 and -9 were slightly suppressed by curcumin with a consequent inhibition of cell death. These results suggest that curcumin appears to be an effective anti-PhIP food additive likely acting through multiple molecular targets.

Exosomes released from Doxorubicin-treated breast tumor promote lung metastasis through miR126 mediated induction of MDSCs (TUM10P.1060)

Chemotherapy induces myeloid-derived suppressor cells (MDSCs) which promote tumor metastasis. However, the molecular basis for chemotherapy induced MDSCs remains poorly understood. Here, we demonstrate that Doxorubicin-derived MDSC promote cancer progression via their effect on angiogenesis and the formation of a premetastatic niche. miRNA-containing exosomes from doxorubicin-treated MDSC exert more potent proangiogenic effects. We also demonstrate high level of MiR-126 was detected in Doxorubicin-derived exosomes, and inhibition of miR126 encapsulated in exosomes impaired proangiogenic effects of Doxorubicin-derived MDSC. Furthermore, nanoparticle-mediated targeting delivery of anti-miR-126 to MDSCs improves Doxorubicin-based therapeutic responses, leading to inhibition of lung metastasis. Collectively, our finding provides a compelling rationale to develop therapeutic strategy for overcoming chemotherapy resistance.

Abstract 4106: Curcumin inhibit PhIP induced cytotoxicity by inhibiting ROS production, DNA strand breaks and DNA adducts formation in MCF 10A cells

PhIP is a known food carcinogen found in well done meat which causes several cancers including breast cancer. PhIP metabolites produce DNA adduct and DNA strand breaks. Curcumin, obtained from the rhizome of Curcuma longa, has potent anticancer activity. So far none of the study demonstrates the inhibition of PhIP induced cytotoxicity by the co-treatment of Curcumin in normal breast epithelial cells in vitro. Therefore, we developed a model system using the MCF 10A normal breast epithelial cells to study the PhIP cytotoxicity and if cells are co-cultured with Curcumin and PhIP how it affects. Consequently, the core signaling pathways have been explored to evaluate the efficacy of Curcumin. In this study, the effectiveness of Curcumin was investigated in MCF 10A cells along with PhIP. The cytotoxic ability was detected with MTT assay, ROS activation by DCF, the influence of the cell cycle was checked with flow cytometry, DNA damage by comet assay, DNA adduct formation by anti-PhIP DNA primary, and apoptosis by Annexin-V-FITC staining. The influence of the core signaling pathways was evaluated by RT PCR and/or Western blotting which included Nrf2 (GSR, GPX, NQO1), FOXO (Catalase, GADD45, PRDX3) targets; DNA repair genes/proteins BRCA1, H2AFX and PARP-1; and tumor suppressor P16 gene expression. PhIP cytotoxicity induced the expression of various antioxidant and DNA repair genes on MCF-10A cells but co-treatment of Curcumin retained its expression level similar to untreated groups. Additionally, Curcumin co- treatment increased the expression level of tumor suppressor expression gene P-53. Expression of antioxidants genes was induced by PhIP whereas Curcumin significantly suppress the PhIP induced ROS activation, DNA strand breaks and DNA adduct formation and consequently inhibited the cell death. In conclusion, Curcumin appears to be effective to inhibit P450 mediated ROS production and PhIP-DNA adducts which consequently reduces DNA damage.

Citation Format: Ashok K. Jain, Abhilash Samykutty, Carissa L. Jackson, Muthusamy Thangaraju, Darren D. Browning. Curcumin inhibit PhIP induced cytotoxicity by inhibiting ROS production, DNA strand breaks and DNA adducts formation in MCF 10A cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4106. doi:10.1158/1538-7445.AM2014-4106

Cathepsin B degradable star-shaped peptidic macromolecules for delivery of 2-methoxyestradiol

2-Methoxyestradiol (2ME), a natural metabolite of estradiol, has antiproliferative and antiangiogenic activity. However, its clinical success is limited due to poor water solubility and poor pharmacokinetic parameters suggesting the need for a delivery vehicle. In this study we evaluated cathepsin B degradable star-shaped peptidic macromolecules (SPMs) that can potentially be used to create higher generation and high molecular weight peptidic polymer as delivery vehicle of 2ME. Two peptidic macromolecules having positively charged amine (ASPM) or negatively charged carboxyl surface groups (CSPM) were synthesized and evaluated for their degradation in the presence of cathepsin B and stability in the presence of neutral or acidic buffer and serum. Both ASPM and CSPM degraded rapidly in the presence of cathepsin B. Both were stable in neutral and acidic buffer whereas only CSPM exhibited substantial stability in the presence of serum. Both macromolecules were nontoxic toward breast cancer cells whereas 2ME-containing macromolecules exhibited antiproliferative activity in the micromolar range. Overall, results from the current study indicate that tetrapeptide GFLG can be used to create star-shaped macromolecules that are degraded in the presence of cathepsin B and have the potential to be developed as delivery vehicles of 2ME.

Abstract 1109: Characterization of hepatoma-derived growth factor (HDGF) as a novel survival related protein in prostate cancer cells

Prostate cancer (PCa) is a leading cause of death by cancer in men, resulting in approximately 32,000 deaths each year. While the cause of PCa is not clearly known at this time, some risk factors include age, diet, race, and activation of certain oncogenes. Hepatoma-derived growth factor (HDGF) is a recently discovered oncogene and a key mitogenic growth factor which is activated in lung, liver, and skin cancers, however, its role in the development of PCa is unknown. Therefore, the goal of this study is to characterize the role of HDGF in prostate carcinogenesis. A normal prostate cell line, RWPE-1, and four different PCa cell lines, LNCaP, 22RV1, DU145, and PC-3, were analyzed for their expression level of HDGF by western blot analysis. Results of this evaluation revealed that HDGF is over-expressed in multiple PCa cell lines while minimally expressed in RWPE-1 cells. When the HDGF gene is ectopically over-expressed in normal RWPE-1 cells, proliferative rate was increased by 1.5 fold compared to the normal cells, suggesting that HDGF has growth stimulating activity. On the contrary, down regulation of HDGF expression by siRNA significantly inhibited the survival of both androgen dependent (LNCaP) and androgen independent (PC-3) PCa cells. DNA content analysis of RWPE-1 cells stably expressing HDGF by flow cytometry showed that the majority of the cells were in the G2/M phase (55%) of the cell cycle while only 28% of the control RWPE-1 cells were at G2/M phase implying HDGF may have a mitotic function in prostate cells. Furthermore, AKT (phosphorylated form) and NFκB (p65 domain) signaling molecules were found to be activated in RWPE-1 cells expressing HDGF. This activation resulted in the increase of anti-apoptotic molecules Cyclin-E and BCL-2 and the simultaneous decrease in the pro-apoptotic molecule Bax. Activation of AKT-NFκB pathway plays a vital role in the carcinogenesis of several cancers, including PCa. Thus, HDGF over-expression may play a role in regulating this survival pathway in prostate carcinogenesis. Collectively, the results of this study suggest that HDGF is a key player in the development of PCa and may serve as a target for chemopreventive or chemotherapeutic strategies in PCa.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1109. doi:10.1158/1538-7445.AM2011-1109