Tumor-targeting Performance Research Articles

Effect of molar dose on the in vivo tissue biodistribution profile of FAP-targeted radioligand therapeutics.

177Lu-OncoFAP-23 is a novel FAP-targeted radioligand therapeutic (RLT) with high and prolonged tumor residence time and promising preclinical efficacy. In this work, we investigated the correlation between the injected molar dose and the in vivo tumor-to-organ ratios and tumor-targeting performance of 177Lu-OncoFAP-23. We evaluated the quantitative biodistribution profile of 177Lu-OncoFAP-23 at different molar doses (i.e., 3 to 2250nmol/kg) in tumor-bearing mice by means of ex vivo gamma counting, we included 177Lu-OncoFAP and 177Lu-BiOncoFAP as experimental controls. The biodistribution profile of 177Lu-OncoFAP-23 strongly depends on the molar dose injected. Molar doses below 30nmol/kg result in unwanted uptake of the compound in healthy organs, while doses higher than 725nmol/kg determined a reduced tumor uptake due to receptor saturation. We identified an optimal molar dose ranging from 90 to 250nmol/kg, characterized by elevated tumor uptake and adequate tumor-to-organ ratios. 177Lu-OncoFAP-23 presents a favorable in vivo biodistribution profile at molar doses ranging from 90 to 250nmol/kg in tumor-bearing mice. Our results guide the design of the first-in-human Phase I clinical trial with this novel FAP-targeted radioligand therapeutic.

Hydralazine loaded nanodroplets combined with ultrasound-targeted microbubble destruction to induce pyroptosis for tumor treatment

Pyroptosis, a novel type of programmed cell death (PCD), which provides a feasible therapeutic option for the treatment of tumors. However, due to the hypermethylation of the promoter, the critical protein Gasdermin E (GSDME) is lacking in the majority of cancer cells, which cannot start the pyroptosis process and leads to dissatisfactory therapeutic effects. Additionally, the quick clearance, systemic side effects, and low concentration at the tumor site of conventional pyroptosis reagents restrict their use in clinical cancer therapy. Here, we described a combination therapy that induces tumor cell pyroptosis via the use of ultrasound-targeted microbubble destruction (UTMD) in combination with DNA demethylation. The combined application of UTMD and hydralazine-loaded nanodroplets (HYD-NDs) can lead to the rapid release of HYD (a demethylation drug), which can cause the up-regulation of GSDME expression, and produce reactive oxygen species (ROS) by UTMD to cleave up-regulated GSDME, thereby inducing pyroptosis. HYD-NDs combined with ultrasound (US) group had the strongest tumor inhibition effect, and the tumor inhibition rate was 87.15% (HYD-NDs group: 51.41 ± 3.61%, NDs + US group: 32.73%±7.72%), indicating that the strategy had a more significant synergistic anti-tumor effect. In addition, as a new drug delivery carrier, HYD-NDs have great biosafety, tumor targeting, and ultrasound imaging performance. According to the results, the combined therapy reasonably regulated the process of tumor cell pyroptosis, which offered a new strategy for optimizing the therapy of GSDME-silenced solid tumors.

Combined Photothermal Therapy and Cancer Immunotherapy by Immunogenic Hollow Mesoporous Silicon-shelled Gold Nanorods

Hyperthermia can be integrated with tumor-killing chemotherapy, radiotherapy and immunotherapy to give rise to an anti-tumor response. To this end, a nano-delivery system is built, which can connect hyperthermia and immunotherapy. On this basis, the impact of such a combination on the immune function of dendritic cells (DCs) is explored. The core of this system is the photothermal material gold nanorod (GNR), and its surface is covered with a silica shell. Additionally, it also forms a hollow mesoporous structure using the thermal etching approach, followed by modification of targeted molecule folic acid (FA) on its surface, and eventually forms a hollow mesoporous silica gold nanorod (GNR@void@mSiO2) modified by FA. GNR@void@mSiO2-PEG-FA (GVS-FA) performs well in photothermal properties, drug carriage and release and tumor targeting performance. Furthermore, the thermotherapy of tumor cells through in vitro NIR irradiation can directly kill tumor cells by inhibiting proliferation and inducing apoptosis. GVS-FA loaded with imiquimod (R837) can be used as a adjuvant to enhance the immune function of DCs through hyperthermia.

Induction of ferroptosis by artesunate nanoparticles is an effective therapeutic strategy for hepatocellular carcinoma

Artesunate (ART) has great value in the field of tumor therapy. Interestingly, in this study, we found that ART could obviously induce ferroptosis in hepatocellular carcinoma (HCC) cells, but its low water solubility and bioavailability limited its application potential. Hence, we synthesized ART-loaded mesoporous silica nanoparticles (MSNs) conjugated with folic acid (FA) (MSN-ART-FA) with tumor-targeting performance and assessed their characteristics. We evaluated the ability of MSN-ART and MSN-ART-FA to induce ferroptosis of hepatoma cells via testing levels of reactive oxygen species (ROS), Fe2+, malondialdehyde (MDA) and glutathione (GSH), observation of mitochondrial morphology, as well as the expression of key proteins in ferroptosis. The results showed that prepared MSN-ART and MSN-ART-FA could remarkedly improve the bioavailability of ART to enhance ferroptosis, thereby inhibiting cell proliferation, migration and invasion in vitro. Besides, MSN-ART-FA group displayed slower tumor growth and smaller tumor volumes than MSN-ART group in HepG2 xenograft mouse model. It provided a potential therapeutic option for HCC and expanded the horizon for the clinical treatment of other cancers.Graphical

High Affinity and FAP-Targeted Radiotracers: A Potential Design Strategy to Improve the Pharmacokinetics and Tumor Uptake for FAP Inhibitors.

Fibroblast activation protein (FAP) is overexpressed in cancer-associated fibroblasts, making it an attractive target for both imaging and therapy of malignancy. This study presents a range of novel FAP inhibitors derived from amino derivatives of UAMC1110, incorporating polyethylene glycol and bulky groups containing bifunctional DOTA chelators. The compounds labeled with gallium-68 were developed and characterized to study biodistribution properties and tumor-targeting performance in nude mice bearing U87MG tumor xenografts. Several tracers of interest were screened due to the advantages in imaging and tumor-specific uptake. Positron emission tomography scans revealed that polyethylene glycol-modified 68Ga-3-3 had a rapid penetration within the neoplastic tissue and excellent tumor-to-background contrast. In a comparative biodistribution study, naphthalene-modified 68Ga-6-3 exhibited more significant tumor uptake (∼50% ID/g, 1 h p.i.) than 68Ga-3-3 and 10-fold higher than 68Ga-FAPI-04 under the same conditions. Remarkably, 68Ga-8-1, combining the two structural design strategies, obtains superior imaging performance.

Abstract 1989: DNA-encoded affinity maturation libraries enable the discovery of low picomolar fibroblast activation protein inhibitors suitable for radioligand therapy of solid tumors

Abstract The discovery of potent ligands highly specific to accessible cancer-associated antigens is essential for the development of small molecule therapeutics with broad therapeutic index. DNA-encoded chemical libraries (DELs) can be used to discover novel binders and to improve binding affinity of existing small organic ligands by affinity maturation procedures. OncoFAP is a 680 pM inhibitor of the stromal pan-tumoral antigen Fibroblast Activation Protein (FAP). OncoFAP displays best-in-class tumor targeting performance in patients, although its relatively short half-life limits the applicability as radioligand therapeutic against solid malignancies. We designed three focused affinity maturation DELs, containing 50,730 compounds bearing two sets of building blocks coupled to a propargylglycine central scaffold. Library selections against FAP from multiple species enabled the discovery of novel FAP inhibitors with potencies in the low picomolar range. 177Lu-DOTAGA conjugates of the most potent novel ligands (named “OncoFAP-11” and “BiOncoFAP-11”) localized to tumors implanted in mice, with excellent tumor-to-blood and tumor-to-kidney ratios at late time-points after systemic administration. The high affinity FAP ligands described here enable the efficient delivery of therapeutic radionuclides to tumors with long residence time and with low uptake in normal tissues. The results presented here show that DEL-based affinity maturation procedures can lead to the improvement of the targeting performance of FAP binders, without compromising their tumor selectivity. Citation Format: Sara Puglioli, Luca Prati, Sebastian Oehler, Andrea Galbiati, Dario Neri, Samuele Cazzamalli, Gabriele Bassi, Nicholas Favalli. DNA-encoded affinity maturation libraries enable the discovery of low picomolar fibroblast activation protein inhibitors suitable for radioligand therapy of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1989.

Combined Ibuprofen-Nanoconjugate Micelles with E-Selectin for Effective Sunitinib Anticancer Therapy.

Sunitinib, a first-line therapy with a certain effect, was utilized in the early stages of renal cell carcinoma treatment. However, its clinical toxicity, side effects, and its limited bioavailability, resulted in inadequate clinical therapeutic efficacy. Building neoteric, simple, and safe drug delivery systems with existing drugs offers new options. Therefore, we aimed to construct a micelle to improve the clinical efficacy of sunitinib by reusing ibuprofen. We synthesized the sialic acid-poly (ethylene glycol)-ibuprofen (SA-PEG-IBU) amphipathic conjugate in two-step reaction. The SA-PEG-IBU amphiphilic conjugates can form into stable SPI nanomicelles in aqueous solution, which can be further loaded sunitinib (SU) to obtain the SPI/SU system. Following nanomicelle creation, sialic acid exposed to the nanomicelle surface can recognize the overexpressed E-selectin receptor on the membrane of cancer cells to enhance cellular uptake. The properties of morphology, stability, and drug release about the SPI/SU nanomicelles were investigated. Confocal microscopy and flow cytometry were used to assess the cellular uptake efficiency of nanomicelles in vitro. Finally, a xenograft tumor model in nude mice was constructed to investigate the body distribution and tumor suppression of SPI/SU in vivo. The result showed that SPI nanomicelles exhibited excellent tumor targeting performance and inhibited the migration and invasion of tumor cell in vitro. The SPI nanomicelles can improve the accumulation of drugs in the tumor site that showed effective tumor inhibition in vivo. In addition, H&E staining and immunohistochemical analysis demonstrated that the SPI/SU nanomicelles had a superior therapeutic effect and lower biotoxicity. The SPI/SU nanomicelles displayed excellent anti-tumor ability, and can suppress the metastasis of tumor cell by decreasing the expression of Cyclooxygenase-2 due to the ibuprofen, providing an optimistic clinical application potential by developing a simple but safe drug delivery system.

An iRGD-conjugated photothermal therapy-responsive gold nanoparticle system carrying siCDK7 induces necroptosis and immunotherapeutic responses in lung adenocarcinoma.

Although immunotherapy has improved the clinical treatment of lung adenocarcinoma (LUAD), many tumors have poor responses to immunotherapy. In this study, we confirmed that high expression of Cyclin-Dependent Kinase 7 (CDK7) promoted an immunosuppressive macrophage phenotype and macrophage infiltration in LUAD. Thus, we have developed an internalizing-RGD (iRGD)-conjugated gold nanoparticle (AuNP) system which carries siCDK7 to activate the antitumor immune response. The iRGD-conjugated AuNP/siCDK7 system exhibited good tumor targeting performance and photothermal effects. The AuNP/siCDK7 system with excellent biosafety exerted a significant photothermal antitumor effect by inducing tumor cell necroptosis. Furthermore, the AuNP/siCDK7 system ameliorated the immunosuppressive microenvironment and enhanced the efficacy of anti-PD-1 treatment by increasing CD8+ T cell infiltration and decreasing M2 macrophage infiltration. Hence, this iRGD-conjugated AuNP/siCDK7 system is a potential treatment strategy for lung adenocarcinoma, which exerts its effects by triggering tumor cell necroptosis and immunotherapeutic responses.

Outward Movement of Targeting Ligands from a Built-In Reserve Pool in Nuclease-Resistant 3D Hierarchical DNA Nanocluster for in Vivo High-Precision Cancer Therapy.

Nanostructures made entirely of DNAs display great potential as chemotherapeutic drug carriers but so far cannot achieve sufficient clinic therapy outcomes due to off-target toxicity. In this contribution, an aptamer-embedded hierarchical DNA nanocluster (Apt-eNC) is constructed as an intelligent carrier for cancer-targeted drug delivery. Specifically, Apt-eNC is designed to have a built-in reserve pool in the interior cavity from which aptamers may move outward to function as needed. When surface aptamers are degraded, ones in reserve pool can move outward to offer the compensation, thereby magically preserving tumor-targeting performance in vivo. Even if withstanding extensive aptamer depletion, Apt-eNC displays a 115-fold enhanced cell targeting compared with traditional counterparts and at least 60-fold improved tumor accumulation. Moreover, one Apt-eNC accommodates 5670 chemotherapeutic agents. As such, when systemically administrated into HeLa tumor-bearing BALB/c nude mouse model, drug-loaded Apt-eNC significantly inhibits tumor growth without systemic toxicity, holding great promise for high precision therapy.

Macrophage-mediated delivery of magnetic nanoparticles for enhanced magnetic resonance imaging and magnetothermal therapy of solid tumors

Magnetothermal therapy (MHT) has attracted significant attention due to the advantages of non-/minimal invasiveness, high efficiency, and excellent tissue penetration. However, developing small MHT agents (<50 nm) with excellent magnetothermal conversion performance and high tumor enrichment is a great challenge. Herein, a macrophage-mediated delivery of small Fe@Fe3O4-DHCA nanoparticles (∼14 nm) was designed for enhanced magnetic resonance imaging (MRI) and MHT of solid tumors. Based on the “Trojan horse” loading properties of the macrophages (RAW267.4 cells), the aggregation of Fe@Fe3O4-DHCA nanoparticles in the cells results in an enhanced MRI and magnetothermal performance in vitro. In addition, the MHT effect of RAW267.4 loaded with Fe@Fe3O4-DHCA in vivo is better than that of Fe@Fe3O4-DHCA alone, due to the tumor-targeting performance of RAW267.4 cells. This macrophage-mediated delivery provides a new strategy for the enhanced treatment effect of MHT based on Fe@Fe3O4-DHCA nanoparticles, and has great application potential for clinic tumor therapy.

Abstract LB522: Fibroblast activation protein triggers the release of drug payload from non-internalizing small molecule-drug conjugates in solid tumors

Abstract Small Molecule-Drug Conjugates (SMDCs) are modular anti-cancer pro-drugs that include a tumor-targeting small ligand, a cleavable linker and a potent cytotoxic agent. SMDC products that have been developed for clinical applications are targeting internalizing tumor-associated antigens expressed on the surface of tumor cells. We have recently developed a novel non-internalizing small organic ligand (named OncoFAP) of Fibroblast Activation Protein (FAP), a tumor-associated antigen highly expressed in the stroma of most of solid human malignancies. The tumor targeting performance of OncoFAP has been validated by nuclear medicine studies in patients with various solid tumors. In a previous study, we showed that OncoFAP can be used to produce non-internalizing SMDCs that are effective and well tolerated. Here, we describe a new series of OncoFAP-Drug derivatives based on the MMAE tubulin poison and dipeptide linkers that are selectively cleaved by FAP in the tumor microenvironment. We benchmarked the new SMDCs against OncoFAP-MMAE conjugates displaying linker modules which are widely used in approved and clinical stage Antibody-Drug Conjugates, including structures cleaved by Cathepsin B and by reducing agents. We selected OncoFAP-GlyPro-MMAE as the most efficacious and safe SMDC for further clinical development after quantitatively analyzing the biodistribution of MMAE released by OncoFAP-MMAE conjugates. OncoFAP-GlyPro-MMAE selectively delivers high amounts of MMAE at the site of disease, with a tumor-to-kidney ratio of 7-to-1 and of 16-to-1 at 6- and 24-hours post-injection, respectively. Our molecules based on the OncoFAP tumor-targeting ligand and FAP-cleavable linkers promise to be safe and effective against most of human malignancies. Citation Format: Aureliano Zana, Andrea Galbiati, Ettore Gilardoni, Jacopo Millul, Theo Sturm, Riccardo Stucchi, Matilde Bocci, Abdullah Elsayed, Lisa Nadal, Martina Cirillo, Dario Neri, Samuele Cazzamalli. Fibroblast activation protein triggers the release of drug payload from non-internalizing small molecule-drug conjugates in solid tumors [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 LB522.

Effective Combination of Isoniazid and Core-Shell Magnetic Nanoradiotherapy Against Gastrointestinal Tumor Cell Types.

IntroductionRadiotherapy is a conventional treatment for gastrointestinal tumors. However, its therapeutic effect might not be satisfactory because of factors such as radio-resistance of tumor cells and dose reduction applied to avoid damage to normal tissues. We developed a novel combination therapy involving the use of isoniazid (INH) and core-shell magnetic nanospheres (NPs) to enhance the efficacy of radiotherapy.MethodsMagnetic core-shell NPs were synthesized. The shell manganese dioxide (MnO2) reacted with intracellular glutathione to produce Mn2+, which decomposed hydrogen peroxide (H2O2) to hydroxyl radicals (·OH) in the presence of INH to produce sufficient amount of reactive oxygen species. In addition to this chemodynamic therapy, MnO2 catalyzed H2O2 to O2, which alleviated hypoxia in tumors and thus enhanced the effect of radiotherapy. In addition, iron oxide (Fe3O4) and reduced Mn2+ were potential candidates for T1–T2 dual-mode magnetic resonance imaging (MRI) with remarkable magnetic targeting ability.ResultsNPs exhibited efficient tumor targeting performance under the magnetic field and improved T1/T2 dual-mode MRI, which elevated oxygen levels without toxicity to the mice to achieve remarkable therapeutic outcomes, reaching a tumor inhibition rate of 93.2%. Moreover, chemodynamic therapy mediated by INH and NPs enhanced the therapeutic effect of radiotherapy both in vivo and in vitro.ConclusionThe results demonstrated that the combination of INH and NPs could be a novel strategy for radiosensitization with clinical potential.

An ultra-high-affinity small organic ligand of fibroblast activation protein for tumor-targeting applications

We describe the development of OncoFAP, an ultra-high-affinity ligand of fibroblast activation protein (FAP) for targeting applications with pan-tumoral potential. OncoFAP binds to human FAP with affinity in the subnanomolar concentration range and cross-reacts with the murine isoform of the protein. We generated various fluorescent and radiolabeled derivatives of OncoFAP in order to study biodistribution properties and tumor-targeting performance in preclinical models. Fluorescent derivatives selectively localized in FAP-positive tumors implanted in nude mice with a rapid and homogeneous penetration within the neoplastic tissue. Quantitative in vivo biodistribution studies with a lutetium-177-labeled derivative of OncoFAP revealed a preferential localization in tumors at doses of up to 1,000 nmol/kg. More than 30% of the injected dose had already accumulated in 1 g of tumor 10 min after intravenous injection and persisted for at least 3 h with excellent tumor-to-organ ratios. OncoFAP also served as a modular component for the generation of nonradioactive therapeutic products. A fluorescein conjugate mediated a potent and FAP-dependent tumor cell killing activity in combination with chimeric antigen receptor (CAR) T cells specific to fluorescein. Similarly, a conjugate of OncoFAP with the monomethyl auristatin E-based Vedotin payload was well tolerated and cured tumor-bearing mice in combination with a clinical-stage antibody-interleukin-2 fusion. Collectively, these data support the development of OncoFAP-based products for tumor-targeting applications in patients with cancer.

Stimuli-Responsive Nanomaterials for Smart Tumor-Specific Phototherapeutics.

Phototherapy, a type of photoresponsive regulation of biological activities, together with additional stimuli-responsive features, offers significant potential for enhancing the precision and efficacy of cancer treatments. To achieve tumor-specific therapeutics, numerous studies have focused on the development of smart phototherapeutic nanomaterials (PNMs) that can respond to endogenous pathological characteristics (e. g., mild acidity, the overproduction of glutathione, the overproduction of hydrogen peroxide, the overexpression of specific surface receptors, etc.) present in the tumor and/or exogenous stimuli. Such responsiveness can effectively improve the physicochemical properties, cellular uptake, tumor-targeting performance, and pharmacokinetic profile of PNMs. Herein, we will systematically discuss recent advances in this field. Moreover, potential challenges and future directions in the development of stimuli-responsive PNMs are also presented to support the development of this emerging cutting-edge research area.

Ultrasmall Fe@Fe3O4 nanoparticles as T1–T2 dual-mode MRI contrast agents for targeted tumor imaging

Targeted T1–T2 MRI contrast agents, which can eliminate the difficulty of image matching across multiple imaging instruments and permit specific localization of lesions, are promising candidates for more accurate diagnosis of tumors. In this study, ultrasmall Fe@Fe3O4 nanoparticles were designed and synthesized as T1–T2 dual-mode MRI contrast agents for accurate tumor imaging. First, to investigate the influence of nanoparticle size, Fe@Fe3O4 nanoparticles with diameters of 4, 8, and 12 nm were prepared, among which the 8 nm 3-(3,4-dihydroxyphenyl)propionic acid (DHCA)-modified nanoparticles exhibited the optimal T1–T2 dual-mode MRI performance. Next, to develop a tumor-targeted contrast agent, the DHCA-Fe@Fe3O4 nanoparticles were conjugated with the F56 peptide, which targets the vascular endothelial growth factor receptor, and the resulting F56-DHCA-Fe@Fe3O4 nanoparticles were found to exhibit good T1–T2 dual-mode imaging and tumor-targeting performance both in vitro and in vivo, indicating the nanoparticles represent a new research tool for accurate tumor diagnosis.

Core–Shell Structured NaYF4:Yb,Er Nanoparticles with Excellent Upconversion Luminescent for Targeted Drug Delivery

A core–shell-structured composite by combining mesoporous silica with upconversion luminescence (UCL) property had considerable application potentials in the fields of drug delivery, disease diagnosis, and therapy. In this paper, a monodisperse, core–shell-structured NaYF4:Yb,Er@nSiO2@mSiO2 nanoparticle (UCNP@MSNs-FA) with excellent UCL property was successfully fabricated by a facile two-step sol–gel strategy and by modifying the surface with folic acid (FA) to strengthen its tumor-targeting performance. The properties of the composite were studied extensively, which indicated that UCNP@MSNs-FA possessed good dispersion, typical core–shell-structured with high specific surface area (132.775 m2/g), and excellent UCL property that improve cell imaging and drug delivery. The viability of L929 cells and hemolysis assay demonstrated the good biocompatibility of the composite. By using doxorubicin hydrochloride (DOX) as a model drug, the drug loading content and encapsulation efficiency of UCNP@MSNs-FA could reach as high as 11.2% and 37.3%, respectively, which proved the effectiveness to load anticancer drugs. In addition, the DOX-UCNP@MSNs-FA system exhibited sustained drug release and strong pH-dependent performance, in which the drug release would be accelerated at the slightly acidic microenvironment in the tumor. Moreover, experimental results indicated that DOX-UCNP@MSNs-FA exhibited specific cytotoxicity to KB cells but weakened toxicity to FR-negative cells. Therefore, the as-prepared UCNP@MSNs-FA could be used potential for simultaneous targeted anti-cancer drug delivery and cell imaging and enhance the therapeutic efficacy against FR-positive tumor cells.

Sortase-Mediated Site-Specific Modification of Interleukin-2 for the Generation of a Tumor-Targeting Acetazolamide-Cytokine Conjugate.

Small ligands specific to tumor-associated antigens can be used as alternatives to antibodies for the delivery of small payloads such as radionuclides, cytotoxic drugs, and fluorophores. Their use as a delivery moiety of bioactive proteins such as cytokines remains largely unexplored. Here, we describe the preparation and in vivo characterization of the first small molecule–cytokine conjugate targeting carbonic anhydrase IX (CAIX), a marker of renal cell carcinoma and hypoxia. Site-specific conjugation between interleukin-2 and acetazolamide was obtained by sortase A-mediated transpeptidation. Binding of the conjugate to the cognate CAIX antigen was confirmed by surface plasmon resonance. The in vivo targeting of structures expressing carbonic anhydrase IX was assessed by biodistribution experiments in tumor-bearing mice. Optimization of manufacturability and tumor-targeting performance of acetazolamide–cytokine products will be required in order to enable industrial applications.

Synthesis of NaYF4:Yb,Er upconversion nanoparticle-based optomagnetic multifunctional composite for drug delivery system

Optomagnetic multifunctional composite has attracted much attention in recent years because of its promising application prospect in bioimaging, analysis, detection, disease diagnosis, and targeted drug delivery. To explore a dual-targeted therapy for cancer, a novel class of optomagnetic multifunctional composite (UCNP-Fe3O4@MSNs-FA) was successfully synthesized by using upconversion nanoparticles (UCNPs) as nucleus, embedding Fe3O4 nanoparticles into the SiO2 coating layer, and modifying the surface with folic acid (FA) to strengthen its tumor targeting performance. The properties of the composite were extensively studied. The obtained composite possesses excellent upconversion fluorescence, good dispersion, high specific surface area (229.347 m2/g), and saturation magnetization value (10.9 A·m2/g). Its drug loading content and encapsulation efficiency can reach as high as 14.2% and 47.3%, respectively, using doxorubicin hydrochloride (DOX) as model drug. The DOX-UCNP-Fe3O4@MSNs-FA system shows excellent sustained drug release and strong pH-dependent performance, in which the drug release would be accelerated at the slightly acidic microenvironment in the tumor; thus, the system can realize the targeted treatment of cancers. The viability of L929 cells demonstrates the good biocompatibility of the composite. Furthermore, DOX-UCNP-Fe3O4@MSNs-FA exhibits specific cytotoxicity to folate receptor (FR) positive tumor cells, whereas DOX has weak toxicity to FR-negative cells. Therefore, the as-prepared UCNP-Fe3O4@MSNs-FA can potentially be used as an anti-cancer targeted drug delivery system and enhance the therapeutic efficacy against FR-positive tumor cells.

Abstract 1657: Paired agent fluorescence imaging of cancer in a living mouse using targeted molecular probes with emission wavelengths of 690 and 830 nm

Abstract Targeted fluorescent probes were used for cancer imaging and assessing tumor targeting performance in a living mouse model. Untargeted probes and targeted probes (appended with cRGDfK peptide units for integrin targeting on cancer cells) were fabricated with emission wavelengths of 690 and 830 nm. Selective targeting of cancer cells was proved by series of cell microscopy experiments followed by in vivo imaging of subcutaneous tumors in living mice. The mouse imaging studies included a mock surgery that completely removed a fluorescently labeled tumor. Enhanced tumor accumulation due to probe targeting was first evaluated by conducting Single Agent Imaging (SAI) experiments that compared tumor imaging performance of a targeted probe and untargeted probe in separate mouse cohorts. Although there was imaging evidence for enhanced tumor accumulation of the targeted probe, there was moderate scatter in the data due to tumor-to-tumor variability of the vasculature structure and interstitial pressure. A subsequent Paired Agent Imaging (PAI) study co-injected a binary mixture of targeted probe (with emission at 690 nm) and untargeted probe (with emission at 830 nm) into the same tumor-burdened animal. The conclusion of the PAI experiment also indicated enhanced tumor accumulation of the targeted probe but the statistical significance was much higher, even though the experiment required a much smaller cohort of mice. The imaging data from the PAI experiment was analyzed to determine the targeted probe's Binding Potential (BP) for available integrin receptors within the tumor tissue. In addition, pixelated maps of BP within each tumor indicated a heterogenous spatial distribution of BP values. The results of this study show that PAI is a promising new way to analyze tumor heterogeneity and its eventual use in clinical applications such as targeted therapy, image guided surgery, and personalized medicine. Citation Format: Cynthia L. Spires (Schreiber), Canjia Zhai, Janel Dempsey, Hannah McGarraugh, Braden Matthews, Caroline Christmann, Bradley Smith. Paired agent fluorescence imaging of cancer in a living mouse using targeted molecular probes with emission wavelengths of 690 and 830 nm [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 1657.

Bismuth-Based Nanomaterials: Recent Advances in Tumor Targeting and Synergistic Cancer Therapy Techniques.

Despite all of the efforts in the field of cancer therapy, the heterogeneous properties of tumor cells induce an insufficient therapeutic outcome when treated with conventional monotherapies, necessitating a shift in cancer treatment from monotherapy to combination therapy for complete cancer treatment. Multifunctional bismuth (Bi)-based nanomaterials (NMs) with therapeutic functions hold great promise for the fields of cancer diagnosis and therapy based on their low toxicity, X-ray sensitive capabilities, high atomic number, near-infrared driven semiconductor properties, and low cost. Herein, a comprehensive review of recent advances in various medicinal aspects of Bi-based NMs is presented including: evaluation of in-tumor site accumulation, tumor targeting, and therapeutic performance, as well as the characteristics, benefits, and shortcomings of Bi-based NM-mediated major monotherapies. In addition, the cooperative enhancement mechanisms between two or more of these monotherapies are described in detail to address common challenges in cancer therapy, such as multidrug resistance, hypoxia, and metastasis. Finally, this review opens new insights into the design of multimodal synergistic therapies for potential future clinical applications of Bi-based NMs.