B7-H3, an immunomodulatory protein overexpressed in many cancers, is associated with tumor aggressiveness and poor prognosis, making it a crucial target for imaging to elucidate its role in cancer progression and guide therapeutic interventions. This study employed PET imaging to investigate the in vivo delivery and pharmacokinetics of two anti-B7-H3 antibodies, Ab-1 and Ab-2, in mouse xenograft models with varying B7-H3 expression levels. The antibodies were radiolabeled with [89Zr]Zr and evaluated through PET imaging, biodistribution studies, and in vitro assays to assess binding, tumor uptake, and retention. [89Zr]Zr-Ab-1 demonstrated high initial tumor uptake in B7-H3 positive xenografts but exhibited unexpected decreasing retention over time. This clearance was likely attributed to proteolytic cleavage mediated by matrix metalloproteinases in the tumor and the tumor microenvironment. Conversely, [89Zr]Zr-Ab-2 showed more stable tumor retention but lower overall uptake. Further investigation revealed that Ab-1 had affinity for both 4Ig and 2Ig B7-H3 isoforms, while Ab-2 bound exclusively to the 4Ig isoform. This differential binding to B7-H3 isoforms may explain the observed variations in tumor uptake and retention between the two antibodies. The study provides insights into the complex dynamics of B7-H3 targeted antibodies in vivo, highlighting how antibody characteristics, including isoform-specific binding, and tumor factors influence their behavior. These findings have potential implications for optimizing radiotherapy strategies, suggesting the possibility of tailored approaches based on antibody properties and tumor biology.

Disclosure: S. Kumari: None. R. Sarkar: None. Z. Wang: None. S. Thakur: None. L. Abaandou: None. O. Gavrilova: None. H. Lu: None. L. Lang: None. D. Kiesewetter: None. V. Vasko: None. J. Klubo-Gwiezdzinska: None. Background: Integrin αVβ3, a transmembrane glycoprotein receptor involved in cell adhesion and tumor growth, invasion, angiogenesis, and metastasis, is specifically recognized by cyclic pentapeptide c(RGDfK) containing a tripeptide sequence Arg-Gly-Asp (RGD). The study intends to evaluate if αVβ3 can be a therapeutic target with a new radiolabeled RGD analog, 177Lu-EB-RGD, for thyroid cancer (TC). Methods: mRNA and/or protein expressions of αVβ3 were assessed in The Cancer Genome Atlas (n=496 TC), 14 TC cell lines, and commercially available Human Thyroid Cancer Tissue Microarray with 70 TC and 10 normal thyroid tissue samples. Well-established, clinically relevant BRS score was used to determine if the TC was BRAF-like (BRS from -1 to 0) or RAS-like (BRS from 0 to 1). Western blotting and membranous staining with flow cytometry was conducted to measure the expression of αVβ3 in TC cell lines and to select the ones with variable αVβ3 expression. Saturation binding analysis was performed to determine radiopeptide binding to TC cells and a maximum binding affinity (Bmax) was quantified. Mouse xenograft models utilizing cell lines with a high and low αVβ3 cell surface expression were treated with either standard care therapy with Lenvatinib (L), 0.5 mCi of 177Lu-EB-RGD (177Lu), combination therapy with 177Lu+L or placebo, and microPET imaging was performed. A p≤0.05 was rendered statistically significant.Results: Analysis of mRNAseq of 496 TC tissues revealed that αVβ3 is expressed in TC. Immunostaining indicated a significantly higher αVβ3 expression in papillary TC as compared to follicular TC (p=0.03) and normal thyroid (p<0.001). However, poorly differentiated TC exhibited no difference in expression compared to papillary TC (p=0.52). Also, BRAF-like TC cell lines had increased protein expressions of αV (Spearman correlation: r=-0.78, αV vs BRS) and β3 (r=-0.7, β3 vs BRS) compared to the RAS-like cell lines. The cell surface expression of αVβ3 was significantly higher in OCUT2 as compared with FTC133 (p<0.0001), which was corroborated by the radioligand-to-receptor binding capacity showing Bmax values of 382.2 and 79.35 fmol for OCUT2 and FTC133, respectively. TC xenograft mouse models demonstrated that 177Lu-EB-RGD therapy decreased tumor growth in the model characterized by high αVβ3 cell surface expression (OCUT2), but not in a model with low αVβ3 level (FTC133). Moreover, 177Lu+L resulted in a larger reduction of tumor growth as compared to L monotherapy (p=0.05). There was no difference between 177Lu and 177Lu+L therapy outcomes (p=0.99). Conclusions: The αVβ3 integrin is highly expressed in a subset of TC and can be successfully targeted by 177Lu-EB-RGD. The higher growth inhibitory potency of 177Lu-EB-RGD compared with current standard care monotherapy with Lenvatinib provides a translational perspective for this radioligand to be utilized in patients with progressive TC. Presentation: Sunday, July 13, 2025

Abstract Tuberculosis remains a large global disease burden for which treatment regimens are protracted and monitoring of disease activity difficult. Existing detection methods rely almost exclusively on bacterial culture from sputum which limits sampling to organisms on the pulmonary surface. Advances in monitoring tuberculous lesions have utilized the common glucoside [18F]FDG, yet lack specificity to the causative pathogen Mycobacterium tuberculosis (Mtb) and so do not directly correlate with pathogen viability. Here we show that a close mimic that is also positron-emitting of the non-mammalian Mtb disaccharide trehalose – 2-[18F]fluoro-2-deoxytrehalose ([18F]FDT) – is a mechanism-based reporter of Mycobacteria-selective enzyme activity in vivo. Use of [18F]FDT in the imaging of Mtb in diverse models of disease, including non-human primates, successfully co-opts Mtb-mediated processing of trehalose to allow the specific imaging of TB-associated lesions and to monitor the effects of treatment. A pyrogen-free, direct enzyme-catalyzed process for its radiochemical synthesis allows the ready production of [18F]FDT from the most globally-abundant organic 18F-containing molecule, [18F]FDG. The full, pre-clinical validation of both production method and [18F]FDT now creates a new, bacterium-selective candidate for clinical evaluation. We anticipate that this distributable technology to generate clinical-grade [18F]FDT directly from the widely-available clinical reagent [18F]FDG, without need for either custom-made radioisotope generation or specialist chemical methods and/or facilities, could now usher in global, democratized access to a TB-specific PET tracer.

Activation of the innate immune Stimulator of Interferon Genes (STING) pathway potentiates antitumor immunity. However, delivering STING agonists systemically to tumors presents a formidable challenge, and resistance to STING monotherapy has emerged in clinical trials with diminishing natural killer (NK) cell proliferation. Here, we encapsulated the STING agonist diABZI within polymersomes containing a Type I photosensitizer (NBS), creating a nanoagonist (PNBS/diABZI) for highly responsive tumor immunotherapy. This structure promoted H-aggregation and intersystem crossing of NBS, resulting in a ∼ 3-fold amplification in superoxide anion and singlet oxygen generation. The photodynamic therapy directly damaged hypoxia tumor cells and stimulated the proliferation of NK cells and cytotoxic T lymphocytes, thereby sensitizing STING immunotherapy. A single systemic intravenous administration of PNBS/diABZI eradicated orthotopic mammary tumors in murine models, achieving long-term antitumor immune memory to inhibit tumor recurrence and metastasis and significantly improving long-term tumor-free survival. This work provides a design rule for boosting reactive oxygen species production by promoting the intersystem crossing process, highlighting the potential of Type I photosensitizer-polymer vehicles for augmenting STING immunotherapy.

Background: Integrins are cell adhesion receptors consisting of 18α and 8β subunits. A subset of integrins (αvβ3) recognizes Arg-Gly-Asp (RGD) peptide motifs which are involved in the neovascularization and progression of various cancers. The aim of the study was to investigate if αvβ3 can serve as a molecular target for the treatment of thyroid cancer (TC) with a novel radiolabeled RGD analog 177Lu-EB-RGD. Methods: Integrin αvβ3 mRNA and/or protein expression was evaluated in 496 TC included in The Cancer Genome Atlas, tissue microarray including 70 TC and 10 normal thyroid samples, and 14 TC cell lines. BRAF-like or RAS-like expression profile was determined through standard BRS scores ranging from -1 to 0 for BRAF-like and 0 to 1 for RAS-like TC. The association between BRS and the αvβ3 expression was tested by the Spearman correlation (r). Nude mice xenografts developing αvβ3 expressing TC after subcutaneous injection of 5*10^6 TC cells were subjected to monotherapy with 0.5 mCi 177Lu-EB-RGD (177Lu) or in combination with Lenvatinib (177Lu+L). The therapeutic efficacy of 177Lu-EB-RGD was compared with standard-of-care Lenvatinib alone (L) and placebo (P). The continuous data were presented as medians with [25-75% interquartile ranges] and compared using Kruskal-Wallis test. The mixed-effects models were used for longitudinal data analysis with adjusted p≤ 0.05 considered statistically significant. Results: We found a moderate negative correlation between BRS and αv (r=-0.5, p<0.001), and β3 (r=-0.27, p<0.001), revealing that BRAF-like tumors have a higher mRNA expression of αvβ3 integrins. Consistently, the highest αvβ3 mRNA and/or protein expression was found in the BRAF-like TC cell lines OCUT2 (BRS=-0.56), TPC1 (BRS=-0.4), K1 (BRS=-0.29), and Hurthle TC cell line XTC1 (BRS=-0.46). The immunostaining revealed a higher αvβ3 expression in papillary TC compared with follicular TC (p=0.002), and in normal thyroid (p<0.001). Poorly differentiated TC had a similar αvβ3 expression to papillary TC (p=0.14). In the thyroid cancer xenograft mouse model, all treatment modalities were more effective than the placebo in decreasing tumor size as early as 5 days after therapy initiation. A significant difference in growth curve and tumor volume was maintained at the study endpoint (L 0.584 cm3 [0.196-0.984] vs P 0.911 cm3 [0.183-1.68], p=0.001; 177Lu 0.259 cm3 [0.103-0.376] vs P, p<0.001; and 177Lu+L 0.274 cm3 [0.108-0.406] vs P, p<0.001). The combination therapy (177Lu+L) resulted in decreased tumor volume as compared with monotherapy with Lenvatinib (p=0.05) but had a similar effect as compared with 177Lu-EB-RGD monotherapy (p=0.99). Conclusions: The radiolabeled αvβ3 analog 177Lu-EB-RGD has potent growth inhibitory effects in TC characterized by a high integrins expression. The αvβ3 integrin could potentially serve as a molecular target for therapy with radiolabeled RGD analogs in TC. Citation Format: Sonam Kumari, Zhantong Wang, Shilpa Thakur, Laura Abaandou, Oksana Gavrilova, Huiyan Lu, Lixin Lang, Dale Kiesewetter, Vasyl Vasko, Joanna Klubo-Gwiezdzinska. Radiolabeled αvβ3 analog 177Lu-EB-RGD is an effective therapeutic agent in thyroid cancer xenograft mouse model. [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 3946.

Supplemental figure 4: VAC treatment did not improve the uptake of SST analogs in the tumors of the mice models. (A) Representative PET images comparing the uptake of 86Y-DOTA-EB-TATE between the control and VAC treated FTC133 subcutaneous mice model. The bar graph shows no significant difference in the uptake of 68Ga-DOTA-TATE, 68Ga-DOTA-JR11 and 86Y-DOTA-EB-TATE between the control (n=5) and VAC (n=5) treated mice. The representative immunohistochemistry images show an increased cytoplasmic expression of SSTR2 in the tumors of the VAC treated mice in comparison to the tumors of the control mice (Supplemental Table 2). (B) Representative PET images comparing the uptake of 86Y-DOTA-EB-TATE between the control and VAC treated FTC133 metastatic mice model. The bar graph shows no significant difference in the uptake of 68Ga-DOTA-TATE, 68Ga-DOTA-JR11 and 86Y-DOTA-EB-TATE between the control (n=8-12) and VAC (n=8-12) treated mice. The immunohistochemistry images show no difference in the expression of SSTR2 in the metastatic tumors of the control and VAC treated FTC133 mice (Supplemental Table 2). (C) Representative PET images comparing the uptake of 86Y-DOTA-EB-TATE between the control and VAC treated TT subcutaneous mice model. The bar graph shows no significant difference in the uptake of 68Ga-DOTA-TATE, 68Ga-DOTA-JR11 and 86Y-DOTA-EB-TATE between the control (n=5) and VAC (n=5) treated mice. The representative immunohistochemistry images show no difference in the expression of SSTR2 within the tumors of the control and VAC treated mice (Supplemental Table 2). (D) Representative PET images comparing the uptake of 86Y-DOTA-EB-TATE between the control and VAC treated AR42J subcutaneous mice model. The bar graph shows no significant difference in the uptake of 68Ga-DOTA-TATE, 68Ga-DOTA-JR11 and 86Y-DOTA-EB-TATE between the control (n=4) and VAC (n=5) treated mice. The representative immunohistochemistry images show an increased expression of SSTR2 in the tumors of the VAC treated mice in comparison to the tumors of the control mice (Supplemental Table 2). Tumors (Tu) and metastasis (Met) are indicated by white arrows. The SUV scales range from 0 to 3 for 68Ga-DOTA-TATE and 68Ga-DOTA-JR11 and 0 to 15 for 86Y-DOTA-EB-TATE. Data are presented as mean{plus minus}SD.

Supplemental Table 2. Analysis of the metastatic lesions characterized by the highest 68Ga-DOTATATE maximum standard uptake values (SUVmax) in 25 patients enrolled in the clinical trial. The data on patients with SUVmax in metastatic lesions exceeding 15 are bolded. PTC - papillary thyroid cancer, PTCTC - tall cell variant PTC, HTC - Hurthle cell thyroid cancer, MTC - medullary thyroid cancer. * uptake similar to background uptake

Supplementary figure 8. Experimental design of mice studies. (A) Flow diagram depicts an experimental strategy for PET imaging with different SST analogs in tumor mice models. (B) Flow diagram depicts an experimental strategy for 177Lu-DOTA-EB-TATE therapy in mice models characterized by high- and low- SSTR2 expression and similar tumor growth rate. (C) Flow diagram depicts an experimental strategy involving treatment with different 177Lu-labeled SST analogs in a mice model characterized by high- SSTR2 expression.

Supplemental figure 6: Treatment with epigenetic modulators did not increase 86Y-DOTA-EB-TATE uptake within the tumor and normal tissues of the mice models. (A) The bar graph shows quantification of 86Y-DOTA-EB-TATE in the tumor and normal tissues (liver, kidneys, spleen, heart, and lungs) of the control (n=5) and VAC treated (n=5) FTC133 subcutaneous xenograft mice. p=NS (non-significant) w.r.t corresponding control mice tissues; ***p<0.001, **p<0.01 w.r.t control tumor; ^^^p<0.001, ^^p<0.01, ^p<0.05 w.r.t VAC tumor. C-control; VAC- valproic acid. (B) The bar graph shows quantification of 86Y-DOTA-EB-TATE in the tumor and normal tissues (liver, kidneys, spleen, heart, and lungs) of the control (n=4) and VAC treated (n=5) AR42J subcutaneous xenograft mice. p=NS (non-significant) w.r.t corresponding control mice tissues; **p<0.01, *p<0.05 w.r.t control tumor; ^^^p<0.001 w.r.t VAC tumor. C-control; VAC- valproic acid. (C) The bar graph shows quantification of 86Y-DOTA-EB-TATE in the tumor and normal tissues (liver, kidneys, spleen, heart, and lungs) of the control (n=3) and DEC treated (n=3) FTC133 subcutaneous xenograft mice. p=NS (non-significant) w.r.t corresponding control mice tissues; **p<0.01, *p<0.05 w.r.t control tumor; ^^p<0.01, ^p<0.05 w.r.t DEC tumor. C-control; DEC- decitabine. (D) The bar graph shows quantification of 86Y-DOTA-EB-TATE in the tumor and normal tissues (liver, kidneys, spleen, heart, and lungs) of the control (n=5) and DEC treated (n=3) AR42J subcutaneous xenograft mice. p=NS (non-significant) w.r.t corresponding control mice tissues; **p<0.01, *p<0.05 w.r.t control tumor; ^^p<0.01, ^p<0.05 w.r.t DEC tumor. C-control; DEC- decitabine.

Supplemental figure 5: Decitabine (DEC) treatment did not improve the uptake of 86Y-DOTA-EB-TATE in the tumors of the mice models. (A) Representative PET images comparing the uptake of 86Y-DOTA-EB-TATE between the control and decitabine (DEC) treated FTC133 subcutaneous mice model. The bar graph shows no significant difference in the uptake of 86Y-DOTA-EB-TATE between the control (n=3) and DEC (n=3) treated mice. (B) Representative PET images comparing the uptake of 86Y-DOTA-EB-TATE between the control and DEC treated AR42J subcutaneous mice model. The bar graph shows no significant difference in the uptake of 86Y-DOTA-EB-TATE between the control (n=5) and DEC (n=3) treated mice. Tumors (Tu) are indicated by white arrows.

Supplemental figure 3: VAC inhibits cell proliferation by promoting cell cycle arrest and apoptosis. (A, D, G, J) VAC treatment (2 mM and 4 mM) inhibits cellular proliferation of FTC133 (n=3), BCPAP (n=3), TT (n=3) and AR42J (n=3) cells. ***p<0.001; **p<0.01. C-control; VAC-valproic acid. (B, E, H, K) VAC treatment (2 mM and 4 mM) leads to cell cycle arrest of FTC133 (n=3), BCPAP (n=3), TT (n=3) and AR42J (n=3) cells. C-control; VAC-valproic acid. (C, F, I, L) VAC treatment (2 mM and 4 mM) promotes apoptosis of FTC133 (n=3), BCPAP (n=3), TT (n=3) and AR42J (n=3) cells, respectively. C-control; VAC-valproic acid.

Supplemental figure 2: Valproic acid is a superior epigenetic modifier in upregulating SSTR2 expression in thyroid cancer cell lines. (A, B) VAC (300 ug/mL, equivalent to 2 mM), TAC (500 ng/mL), and DEC (75 ng/mL) treatment upregulates SSTR2 expression in FTC133 (n=3) and BCPAP (n=3) cells. ***p<0.001; **p<0.01; p<0.05. C- control; VAC- valproic acid; TAC- tacedinaline; DEC- decitabine.

Supplemental Table 1: Analysis of immunostaining of SSTR2 in human tissue samples derived from thyroid cancer patients. Score 0-no staining, Score 1-positive staining in <25% of cells, Score 2-positive staining in 25-50% of cells, Score 3-positive staining in >50% of cells. PTC - papillary thyroid cancer, FTC - follicular thyroid cancer, PDTC - poorly differentiated thyroid cancer, MTC - medullary thyroid cancer, HTC - Hürthle cell thyroid cancer.

Supplemental figure 1: SSTR2 is overexpressed in thyroid cancer tissues in comparison to normal thyroid tissues. (A) SSTR2 expression in different stages of PTC. (B) SSTR2 expression in histological subtypes of PTC. (C) Comparison of SSTR2 mRNA expression in different TC cell lines. (D) TT cells had significantly higher expression than BCPAP and FTC133 cells at the mRNA level. *p<0.05, ***p<0.001.

Abstract Purpose: The goal of this study was to analyze the role of somatostatin receptor type 2 (SSTR2) as a molecular target for the imaging and treatment of thyroid cancer through analysis of SSTR2 expression and its epigenetic modulation and testing tumor uptake of different radiolabeled SSTR2 analogues. Experimental Design: We analyzed SSTR2 expression by immunostaining of 92 thyroid cancer tissue samples and quantified standard uptake values (SUVmax) of SSTR2 analogue, 68Ga-DOTA-TATE, by PET/CT imaging in 25 patients with metastatic thyroid cancer. We utilized human thyroid cancer cell lines characterized by differential SSTR2 expression (TT, BCPAP, and FTC133) and rat pancreatic cell line (AR42J) with intrinsically high SSTR2 expression for functional in vitro studies. SSTR2-high (AR42J) and SSTR2-low (FTC133) xenograft mouse models were used to test the uptake of radiolabeled SSTR2 analogues and their therapeutic efficacy in vivo. Results: Thyroid cancer had a higher SSTR2 expression than normal thyroid. Hurthle cell thyroid cancer was characterized by the highest 68Ga-DOTA-TATE uptake [median SUVmax, 16.5 (7.9–29)] than other types of thyroid cancers. In vivo studies demonstrated that radiolabeled DOTA-EB-TATE is characterized by significantly higher tumor uptake than DOTA-TATE (P < 0.001) and DOTA-JR11 (P < 0.001). Treatment with 177Lu-DOTA-EB-TATE extended survival and reduced tumor size in a mouse model characterized by high somatostatin (SST) analogues uptake (SUVmax, 15.16 ± 4.34), but had no effects in a model with low SST analogues uptake (SUVmax, 4.8 ± 0.27). Conclusions: A novel SST analogue, 177Lu-DOTA-EB-TATE, has the potential to be translated from bench to bedside for the targeted therapy of patients characterized by high uptake of SST analogues in metastatic lesions.

Lu-DOTA-EB-TATE, A Radiolabeled Analog of Somatostatin Receptor Type 2, for the Imaging and Treatment of Thyroid Cancer Shilpa Thakur, Brianna Daley, Corina Millo, Craig Cochran, Orit Jacobson, Huiyan Lu, Zhantong Wang, Dale O. Kiesewetter, Xiaoyuan Chen, Vasyl Vasko, Joanna Klubo-Gwiezdzinska Affiliations: Metabolic Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA. Clinical Center, National Institutes of Health, Bethesda, MD, USA. Molecular Tracer and Imaging Core Facility, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA. 4 National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA. Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA. Department of Pediatric Endocrinology, Uniformed Services of the Health Sciences, Bethesda, MD, USA.

Background: Differentiated thyroid cancer (DTC) and medullary thyroid cancer (MTC) are characterized by the overexpression of somatostatin receptor type 2 (SSTR2). There are limited data on the use of SSTR2 as a molecular target for imaging and treatment of DTC and MTC. The goal of our study was to compare the diagnostic accuracy of three different radiolabeled SSTR2 analogs in DTC and MTC mouse models: JR11, an antagonist; DOTATATE, an agonist; and EB-TATE, a novel modified agonist characterized by a longer half-life in the blood. Methods: SSTR2 expression was analyzed in two DTC cell lines (BCPAP and FTC133) and one MTC cell line (TT) by RT-PCR and immunoblotting. A rat pancreatic cell line (AR42J), characterized by intrinsically high SSTR2 expression, was used as a positive control. A metastatic (MT) mouse model was generated using immunocompromised mice which develop lung and liver metastases after tail vein injection of FTC133 and BCPAP cells. Subcutaneous (SC) xenograft mice models were generated by injecting FTC133, BCPAP, TT, and AR42J cells. The fast-growing FTC133 and AR42J cells formed soft, sizable tumors in 2 weeks, while BCPAP and TT cells formed very solid tumors after 4 and 8 weeks, respectively. Maximum standard uptake value of 68Ga-DOTATATE, 86Y-EB-TATE, and 68Ga-DOTA-JR11 (IPSEN®) was compared in each mouse in MT and SC models by PET/CT. Results: Among thyroid cancer cell lines, TT cells were characterized by the highest SSTR2 expression at the mRNA level compared with BCPAP (p<0.001) and FTC133 (p<0.001). At the protein level, BCPAP and TT cells were characterized by similar SSTR2 expression and FTC133 cells had the lowest expression. Among examined radiolabeled SSTR2 analogs, 86Y-EB-TATE showed the highest tumor uptake in all MT and SC mouse models in comparison to 68Ga-DOTATATE (p< 0.001) and 68Ga-DOTA-JR11, (p<0.001). 68Ga-DOTA-JR11 was characterized by higher tumor uptake than 68Ga-DOTATATE in only the SC FTC133 mouse model (p=0.01). The AR42J mouse model (positive control) had the highest tumor uptake of all three radioactive analogs in comparison to DTC and MTC mice models (p<0.001). Among thyroid cancer mice models, aggressively growing FTC133 tumors were characterized by the highest uptake of 68Ga-DOTA-JR11 and 86Y-EB-TATE compared with slow-growing BCPAP (p<0.01 & p<0.001, respectively) and TT tumors (p<0.05 & p<0.001, respectively) in SC mice models. There was no significant difference in the 68Ga-DOTATATE uptake between FTC133 and BCPAP mice models (p= 0.97), which were characterized by significantly higher uptake than the TT mouse model (p= 0.01 & 0.03, respectively). Conclusion: We show for the first time that a novel SSTR2 analog 86Y-EB-TATE is characterized by superior tumor uptake compared to 68Ga-DOTATATE and 68Ga-DOTA-JR11 in TC mice models. Uptake of the radiolabeled analogs not only depends on SSTR2 expression levels, but also on the tumor aggressiveness.

The effectiveness of numerous molecular drugs is hampered by their poor pharmacokinetics. Different from previous approaches with limited effectiveness, most recently, emerging high-affinity albumin binding moieties (ABMs) for in vivo hitchhiking of endogenous albumin opens up an avenue to chaperone small molecules for long-acting therapeutics. Although several FDA-approved fatty acids have shown prolonged residence and therapeutic effect, an easily synthesized, water-soluble, and high-efficiency ABM with versatile drug loading ability is urgently needed to improve the therapeutic efficacy of short-lived constructs. We herein identified an ideal bivalent Evans blue derivative, denoted as N(tEB)2, as a smart ABM-delivery platform to chaperone short-lived molecules, through both computational modeling screening and efficient synthetic schemes. The optimal N(tEB)2 could reversibly link two molecules of albumin through its two binding heads with a preferable spacer, resulting in significantly extended circulation half-life of a preloaded cargo and water-soluble. Notably, this in situ dimerization of albumin was able to sandwich peptide therapeutics to protect them from proteolysis. As an application, we conjugated N(tEB)2 with exendin-4 for long-acting glucose control in a diabetic mouse model, and it was superior to both previously tested NtEB-exendin-4 (Abextide) and the newly FDA-approved semaglutide, which has been arguably the best commercial weekly formula so far. Hence, this novel albumin binder has excellent clinical potential for next-generation biomimetic drug delivery systems.

A major concern about glucose oxidase (GOx)-mediated cancer starvation therapy is its ability to induce serious oxidative damage to normal tissues through the massive production of H2O2 byproducts in the oxygen-involved glucose decomposition reaction, which may be addressed by using a H2O2 scavenger, known as an antioxidation agent. Surprisingly, H2O2 removal accelerates the aerobic glycometabolism of tumors by activating the H2O2-dependent "redox signaling" pathway of cancer cells. Simultaneous oxygen depletion further aggravates tumor hypoxia to increase the toxicity of a bioreductive prodrug, such as tirapazamine (TPZ), thereby improving the effectiveness of cancer starvation therapy and bioreductive chemotherapy. Herein, a "nitrogen-protected silica template" method is proposed to design a nanoantioxidant called an organosilica-based hollow mesoporous bilirubin nanoparticle (HMBRN), which can act as an excellent nanocarrier to codeliver GOx and TPZ. In addition to efficient removal of H2O2 for self-protection of normal tissues via antioxidation, GOx/TPZ-coloaded HMBRN can also rapidly deplete intratumoral glucose/oxygen to promote a synergistic starvation-enhanced bioreductive chemotherapeutic effect for the substantial suppression of solid tumor growth. Distinct from the simple combination of two treatments, this study introduces antioxidation-activated self-protection nanotechnology for the significant improvement of tumor-specific deoxygenation-driven synergistic treatment efficacy without additional external energy input, thus realizing the renaissance of precise endogenous cancer therapy with negligible side effects.