Tumor Neovasculature Research Articles

Fisheye piezo polymer detector for scanning optoacoustic angiography of experimental neoplasms

A number of optoacoustic (or photoacoustic) microscopy and mesoscopy techniques have successfully been employed for non-invasive tumor angiography. However, accurate rendering of tortuous and multidirectional neoplastic vessels is commonly hindered by the limited aperture size, narrow bandwidth and insufficient angular coverage of commercially available ultrasound transducers. We exploited the excellent flexibility and elasticity of a piezo polymer (PVDF) material to devise a fisheye-shape ultrasound detector with a high numerical aperture of 0.9, wide 1–30 MHz detection bandwidth and 27 mm diameter aperture suitable for imaging tumors of various size. We show theoretically and experimentally that the wide detector’s view-angle and bandwidth are paramount for achieving a detailed visualization of the intricate arbitrarily-oriented neovasculature in experimental tumors. The developed approach is shown to be well adapted to the tasks of experimental oncology thus allows to better exploit the angiographic potential of optoacoustics.

Abstract 1807: CB307: a novel targeted CD137 agonist for enhancement of immune cell responses to PSMA+ tumors

Abstract Introduction: CD137 (HGNC:TNFRSF9, 4-1BB) is a TNF receptor superfamily costimulatory receptor expressed by T cells and NK cells. Upon engagement, CD137 enhances immune cell survival, proliferation, cytokine production and memory formation. CD137 agonists in the clinic have shown tantalizing anti-tumor effects, however, hepatic toxicity has hampered clinical utility. To circumvent this limitation, we developed CB307, a half-life extended heavy-chain only Humabody® that selectively agonizes CD137 only in the presence of prostate specific membrane antigen (PSMA, HGNC:FOLH1). PSMA is highly upregulated on tumor cells in prostate cancer and tumor neovasculature in other solid tumors including lung (NSCLC), kidney (clear cell RCC), bladder and colorectal cancers. CB307 enhances immune cell activation in a PSMA-dependent manner. We present here preclinical mechanistic differentiators of CB307 with respect to non-targeted CD137 agonists. Methods: CD137 agonism, immune cell activation and cytokine secretion were evaluated in vitro using coculture assays in the presence/absence of PSMA-expressing tumor cells and in vivo with a transgenic mouse syngeneic tumor model. The ability of CB307 or non-targeted CD137 agonists to enhance tumor cell killing was additionally characterized in 3D spheroid cocultures. In vitro cocultures were used to determine the impact of PSMA expression level on CB307 activity. CB307 was evaluated as a single agent and in combination with PD-1 or PD-L1 inhibitors; tumoral checkpoint contribution was investigated using isogenic PD-L1 positive vs. PD-L1 CRISPR-deleted tumor cells. Results: CB307 or PD-1/PD-L1 inhibition alone induced IL-2 secretion in PBMC/PSMA-expressing tumor cell cocultures; this effect was synergistically enhanced when CB307 was combined with either PD-1 or PD-L1 inhibition. CB307 augmented tumor cell killing in 3D spheroids containing PSMA-expressing cells. Enhanced tumor cell killing was observed in spheroid cultures containing CB307 in combination with PD-1/PD-L1 inhibition. In in vivo pharmacology studies in a syngeneic mouse model, CB307 demonstrated statistically significant inhibition of tumor growth versus control without peripheral T cell activation - consistent with pharmacology restricted to the PSMA+ tumor microenvironment, whereas an anti-CD137 monoclonal antibody induced tumor growth inhibition accompanied by peripheral immune cell proliferation and cytokine production. Summary: CB307 is a novel CD137 agonist that selectively enhances immune cell activity only in the presence of PSMA-positive cells. Our data demonstrate PSMA-targeted CB307 immunological pharmacology both in vitro and in vivo which has supported the ongoing Phase 1 ‘POTENTIA’ clinical trial (NCT04839991). Citation Format: Andrew J. Pierce, Phillip M. Brailey, Sophie Archer, Clare Song, Anca-Giuilia Cionca, Joanne Fernando, Phillip D. Bartlett, Philip Bland-Ward. CB307: a novel targeted CD137 agonist for enhancement of immune cell responses to PSMA+ 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 1807.

Abstract 4088: A neovasculature-inducible CA9 CAR resistant to FASL and TGFb mediated suppression for the treatment of ccRCC

Abstract Clinically effective CAR-T cell therapy for solid tumors, such as clear cell renal cell carcinoma (ccRCC), will require substantial T cell engineering to increase their specificity and potency. We have developed an Integrated Circuit T cell (ICT) that encodes multiple synthetic “modules” in order to overcome diverse barriers to efficacy in ccRCC; ICT cells are generated via CRISPR-mediated, targeted knock-in of a single large transgene into the novel GS94 safe-harbor locus. Both primary and metastatic sites of ccRCC are highly vascularized, with the majority of tumor cells expressing elevated levels of carbonic anhydrase IX (CA9), suggesting CA9 may be an excellent CAR target. However, CA9 is also expressed in healthy bile ducts and stomach tissue which has led to on-target, off-tumor toxicities in patients treated with constitutive CA9 CAR T cells. To improve the therapeutic index of CA9 CAR T cells, we developed an “AND” logic gated ICT cell that requires the presence of two antigens to trigger tumor cell killing, thereby enhancing tumor specificity. Induction of the CA9 CAR is gated on the expression of PSMA found on the tumor neovasculature of ccRCC. Importantly, PSMA and CA9 are not co-expressed in normal tissues. When the anti-PSMA priming receptor (PrimeRTM) binds PSMA, PrimeRTM engagement triggers proteolytic release of a chimeric, fully human transcription factor that induces expression of a CA9 CAR. We confirmed the feasibility of vascular priming using a transwell assay where ICTs were primed by a PSMA expressing endothelial cell line and then migrated across the transwell membrane to kill CA9 expressing RCC cells. In addition, a dual flank xenograft model was used to show logic gated circuits selectively kill tumors that express both CA9 and PSMA, and not tumors that express CA9 alone. Transforming growth factor beta (TGFb) is an immunosuppressive cytokine known to be highly expressed in ccRCC. To further increase the potency and persistence of the ICT cells an shRNA cassette was developed targeting both FAS and TGFBR2, a receptor required for TGFB signaling in T cells. Addition of FAS/TGFBR2 shRNA enhanced antitumor activity of PSMAxCA9 logic gate expressing T cells during in vitro chronic stimulation assays conducted in the presence of exogenous TGFb. Furthermore, FAS/TGFBR shRNA containing ICTs demonstrated enhanced antitumor activity in multiple xenograft RCC models. Collectively, these results demonstrate that PSMAxCA9 ICT cells can (i) selectively target antigens that cannot be safely targeted by conventional CARs and (ii) overcome multiple suppressive mechanisms in the tumor microenvironment. Citation Format: Angela C. Boroughs, Irene Scarfo, Nickolas Attanasio, Thomas Gardner, Jenessa B. Smith, Jennifer McDevitt, Laura Lim, Nishant Mehta, Suchismita Mohanty, James Zhang, Eric Cui, Vibhavari Sail, Amanda Fearon, Samuel Williams, Stephen Santoro, W. Nicholas Haining, Levi Gray-Rupp. A neovasculature-inducible CA9 CAR resistant to FASL and TGFb mediated suppression for the treatment of ccRCC. [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 4088.

Toward the clinical application of ultrasound molecular imaging in the early detection of breast cancer

Ultrasound molecular imaging has large potential in the early detection of breast cancer, particularly in women with radiographically dense breasts. In ultrasound molecular imaging, a molecularly-targeted ligand attached to a microbubble binds to proteins expressed on the tumor neovasculature to produce contrast that can identify cancer at an early stage. Keys to successful ultrasound molecular imaging are: (1) a molecular target highly specific to breast cancer; and (2) a sensitive imaging system that can visualize bound microbubbles while suppressing bubble signal from the background. In addition, the system must integrate with existing ultrasound imaging workflow in breast imaging clinics. We present our current progress on the development of a real-time ultrasound molecular imaging platform that consists of a novel microbubble targeted to the B7-H3 biomarker (a vascular biomarker highly specific to breast cancer and not expressed in benign disease processes) alongside a nondestructive and real-time imaging technology, based on a neural network design for contrast imaging to enable real-time high-sensitivity imaging of the novel targeted contrast agent. Although we present the results and current status of this system in preclinical models of breast cancer, the targeted microbubble is designed to be pharmaceutical grade to allow it to be injected in humans, and the imaging technology is designed such that it is compatible with current clinical workflow and operation of breast ultrasound imaging.

Palmitoyl Carnitine-Anchored Nanoliposomes for Neovasculature-Specific Delivery of Gemcitabine Elaidate to Treat Pancreatic Cancer

Being the fourth most fatal malignancy worldwide, pancreatic cancer is on track to become the second leading cause of cancer-related deaths in the United States by 2030. Gemcitabine is a first-line chemotherapeutic agent for pancreatic ductal adenocarcinoma (PDAC). Gemcitabine Elaidate (Gem Elaidate) is a lipophilic derivative which allows hENT1-independent intracellular delivery of gemcitabine and better pharmacokinetics and entrapment in a nanocarrier. Cancer cells and neovasculature are negatively charged compared to healthy cells. Palmitoyl-DL-carnitine chloride (PC) is a Protein kinase C (PKC) inhibitor which also provides a cationic surface charge to nanoliposomes for targeting tumor neovasculature and augmented anticancer potency. The objectives of our study are: (a) to develop and characterize a PKC inhibitor-anchored Gem Elaidate-loaded PEGylated nanoliposome (PGPLs) and (b) to investigate the anticancer activity of Gem Elaidate and PGPLs in 2D and 3D models of pancreatic cancer. The optimized PGPLs resulted in a particle size of 80 ± 2.31 nm, a polydispersity index of 0.15 ± 0.05 and a ζ-potential of +31.6 ± 3.54 mV, with a 93.25% encapsulation efficiency of Gem Elaidate in PGPLs. Our results demonstrate higher cellular uptake, inhibition in migration, as well as angiogenesis potential and significant apoptosis induced by PGPLs in 3D multicellular tumor spheroids of pancreatic cancer cells. Hence, PGPLs could be an effective and novel nanoformulation for the neovasculature-specific delivery of Gemcitabine Elaidate to treat PDAC.

PSMA Immunohistochemistry in Hepatic Neoplasms: A Promising Diagnostic Marker With Potential Theranostic Applications.

Accurate classification of well-differentiated hepatocellular neoplasms can be challenging especially in core biopsies. Prostate-specific membrane antigen (PSMA) has been shown to highlight tumor-associated neovasculature in many nonprostatic solid tumors including hepatocellular carcinoma (HCC). Archived 164 hepatectomies and explants with 68 HCCs, 31 hepatocellular adenoma (HA), 24 dysplastic nodules (DN), and 42 metastases were retrieved, and pathologic parameters were evaluated. Sensitivity, specificity, accuracy, positive, and negative predictive values for correct diagnosis of HCC were calculated for PSMA and CD34 immunostains in tissue sections and HCC tissue microarrays. PSMA positivity was defined as capillarized sinusoidal/tumor-associated vessel staining involving ≥5% of the tumor area. In all, 55/68 (80.9%) HCC and 37/42 (88.1%) of liver metastasis were PSMA positive. PSMA was negative in HA, DN, and background liver (100% specificity). CD34 had a 98.5% sensitivity but a 65.5% specificity in identifying HCC. PSMA sensitivity remained high in the HCC tissue microarray (89.7%). PSMA was more accurate than CD34 (95.5% vs. 69.7%) in distinguishing grade 1 HCC from HA and high-grade DN while retaining high sensitivity (80%). The degree of PSMA positivity in HCC was greater in older, male, and human immunodeficiency virus patients ( P <0.05). No associations were found between PSMA staining and other tumor parameters ( P >0.05). PSMA is a marker of neoangiogenesis with increased expression in both primary and metastatic hepatic malignancies. Neovascular PSMA expression is more specific and accurate than CD34 for differentiating HCC from benign and precursor hepatic lesions. Diagnostic and therapeutic utility of PSMA radioligands in malignant liver neoplasms warrant further clinical investigations.

Abstract CT211: A phase 1 dose-escalation and dose-expansion study to evaluate the safety, pharmacokinetics, and anti- tumor activity of ARX517 in subjects with advanced solid tumors resistant or refractory to standard therapies (APEX-01 trial, NCT04662580)

Abstract Background: Novel anti-PSMA (prostate-specific membrane antigen) targeted therapies have exhibited encouraging antitumor activity in prostate cancer and most non-prostate solid tumors express PSMA in tumor neovasculature. ARX517 is an antibody drug conjugate composed of a fully humanized anti-PSMA monoclonal antibody linked to pAF-AS269, a potent microtubule inhibitor. Upon binding to PSMA on the surface of cancer cells, ARX517 is internalized and pAF-AS269 is released following lysosomal metabolism. Methods: This Phase 1, dose-escalation and dose-expansion study is evaluating the safety, pharmacokinetics, and preliminary anti-tumor activity of ARX517 in adults with prostate cancer or other solid tumors whose disease is resistant or refractory to standard therapies. Patients must have metastatic castration-resistant prostate cancer refractory to standard therapies, including abiraterone, darolutamide, apalutamide or enzalutamide and progression by Prostate Cancer Working Group criteria. Non-prostate advanced solid tumors must be pathologically confirmed, metastatic, or unresectable solid tumors that have disease progression despite at least 1 prior standard of care systemic treatment and have no satisfactory treatment alternatives. All patients must have adequate organ function and any brain metastasis must demonstrate radiographic stability. Exploratory pharmacodynamic assessment includes PSMA-PET/CT imaging, which is optional for low dose cohorts but required starting at 1.4 mg/kg dose. Dose-escalation will consist of ascending dose levels of ARX517 administered as a single agent and will use a i3+3 design. The number of subjects in the dose-expansion will be based on the number of doses to be expanded for further evaluation of safety, PK, and clinical activity. Through dose levels one and two, no dose limiting toxicities have been observed. Ascending dose levels of ARX517 as a single agent will be administered until the recommended Phase 2 dose or maximum tolerated dose is determined. Status: ARX517-2011 began recruiting patients in July 2021 and as of January 2022 has completed enrollment in the 3rd cohort of dose-escalation. Citation Format: Russell K. Pachynski, Luke Nordquist, Michael T. Schweizer, John Shen, Nabil Adra, Mehmet A. Bilen, Zachery R. Reichert, Rahul Aggarwal, Bilal A. Siddiqui, Matt Li, Dong Xu, Richard Huhn, Darryl Z. L'Heureux, Jinchun Yan, Ying Buechler, Sulan Yao, John Simitzi, Wenge Shi, Shawn Zhang, Scott T. Tagawa. A phase 1 dose-escalation and dose-expansion study to evaluate the safety, pharmacokinetics, and anti- tumor activity of ARX517 in subjects with advanced solid tumors resistant or refractory to standard therapies (APEX-01 trial, NCT04662580) [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 CT211.

Abstract 2877: CB307: A novel selective CD137 agonist for enhancement of immune cell responses to PSMA+ tumors

Abstract Introduction: CD137 (HGNC:TNFRSF9, 4-1BB) is a TNF receptor superfamily costimulatory receptor expressed by T cells and NK cells. Upon engagement, CD137 enhances immune cell survival, proliferation, cytokine production, and memory formation. As such, CD137 agonists have demonstrated promising pre-clinical anti-tumor effects, however their clinical utility has been limited due to dose-limiting hepatic toxicity. PSMA is highly upregulated on tumor cells and tumor neovasculature in prostate cancer and other solid tumors, including lung (NSCLC), kidney (clear cell RCC), bladder and colorectal cancers. CB307 is a half-life extended Humabody® that selectively agonizes CD137 only in the presence of prostate specific membrane antigen (PSMA, HGNC:FOLH1). CB307 is trispecific with VH components selected for optimal binding to PSMA, CD137 and human serum albumin (HSA). We present here the non-clinical pharmacology and toxicology of CB307. Methods: CD137 agonism and immune cell activation were evaluated in vitro using coculture assays with PSMA-expressing tumor cells as assessed by NFκB-driven luciferase and cytokine secretion. CB307 was evaluated as a single agent and in combination with enzalutamide, PD1 or PDL1 inhibitors. In vivo experiments used a syngeneic mouse system transgenic for the human CD137 immune cell target, and human PSMA expressed on mouse tumor cells. Nonclinical toxicology and pharmacokinetics of CB307 were assessed in cynomolgus macaques. Results: In reporter assays and PBMC cocultures, CB307 activated CD137 only in the presence of PSMA-expressing cells leading to enhanced immune cell activation. Enzalutamide pre-treatment of 22Rv1 (PSMA-low) cells induced a 1.5-fold increase in surface PSMA expression leading to enhanced CB307 activity. CB307 or PD1/PDL1 inhibition alone induced IL-2 secretion in PBMC/PSMA-expressing tumor cell cocultures; this effect was synergistically enhanced when CB307 was combined with either PD1 or PDL1 inhibition. In an in vivo pharmacology study in immuno-competent mice, CB307 demonstrated statistically significant inhibition of tumor growth. CB307 was well-tolerated in a GLP-toxicology study in cynomolgus macaques, with an observed half-life supporting weekly clinical administration. Summary: CB307 is a novel CD137 agonist that selectively enhances immune cell activity in the presence of PSMA-positive cells. Our data demonstrates CB307 immunological pharmacology both in vitro and in vivo which has supported the initiation of the phase I ‘POTENTIA’ clinical trial (NCT04839991). Citation Format: Andrew J. Pierce, Phillip M. Brailey, Clare Song, Sophie Archer, Phillip D. Bartlett, Philip Bland-Ward. CB307: A novel selective CD137 agonist for enhancement of immune cell responses to PSMA+ 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 2877.

Molecular dynamics, MMGBSA, and docking studies of natural products conjugated to tumor-targeted peptide for targeting BRAF V600E and MERTK receptors.

Recent studies have revealed that MERTK and BRAF V600E receptors have been found to be over-expressed in several types of cancers including melanoma, making these receptors targets for drug design. In this study, we have designed novel peptide conjugates with the natural products vanillic acid, thiazole-2-carboxylic acid, cinnamic acid, theanine, and protocatechuic acid. Each of these compounds was conjugated with the tumor targeting peptide sequence TAASGVRSMH, known to bind to NG2 and target tumor neovasculature. We examined their binding affinities and stability with MERTK and BRAF V600E receptors using molecular docking and molecular dynamics studies. Compared to the neat compounds, the peptide conjugates displayed higher binding affinity toward both receptors. In the case of MERTK, the most stable complexes were formed with di-theaninate-peptide, vanillate-peptide, and thiazole-2-amido peptide conjugates and binding occurred in the hinge region. Additionally, it was discovered that the peptide alone also had high binding ability and stability with the MERTK receptor. In the case of BRAF V600E, the peptide conjugates of protocatechuate, vanillate and thiazole-2-amido peptide conjugates showed the formation of the most stable complexes and binding occurred in the ATP binding cleft. Further analysis revealed that the number of hydrogen bonds and hydrophobic interactions played a critical role in enhanced stability of the complexes. Docking studies also revealed that binding affinities for NG2 were similar to MERTK and higher for BRAF V600E. MMGBSA studies of the trajectories revealed that the protocatechuate-peptide conjugate showed the highest binding energy with BRAF V600E while the peptide-TAASGVRSMH showed the highest binding energy with MERTK. ADME studies revealed that each of the compounds showed medium to high permeability toward MDCK cells and were not hERG blockers. Furthermore, the conjugates were not CYP inhibitors or substrates, but they were found to be Pgp substrates. Our results indicated that the protocatechuate-TAASGVRSMH, thiazole-2-amido-TAASGVRSMH, and vanillate-TAASGVRSMH conjugates may be furthered developed for in vitro and in vivo studies as novel tumor targeting compounds for tumor cells over-expressing BRAF V600E, while di-theaninate-amido-TAASGVRSMH and thiazole-2-amido-TAASGVRSMH conjugates may be developed for targeting MERTK receptors. These studies provide insight into the molecular interactions of natural product-peptide conjugates and their potential for binding to and targeting MERTK and BRAF V600E receptors in developing new therapeutics for targeting cancer.

Immunotherapy combining tumor and endothelium cell lysis with immune enforcement by recombinant MIP-3α Newcastle disease virus in a vessel-targeting liposome enhances antitumor immunity

BackgroundSeveral agents for oncolytic immunotherapy have been approved for clinical use, but monotherapy is modest for most oncolytic agents. The combination of several therapeutic strategies through recombinant and nanotechnology to...

A Prostate-Specific Membrane Antigen-Targeted Near-Infrared Conjugate for Identifying Pulmonary Squamous Cell Carcinoma during Resection.

Pulmonary squamous cell carcinoma is the second most common lung cancer subtype and has a low 5-year survival rate at 17.6%. Complete resection with negative margins can be curative, but a high number of patients suffer early postoperative recurrence due to inadequate disease clearance at the index operation. Intraoperative molecular imaging (IMI) with tumor-targeted optical contrast agents is effective in improving resection completeness for other tumor types, but there are no IMI tracers targeted to pulmonary squamous cell carcinoma. In this report, we describe the use of a novel prostate-specific membrane antigen (PSMA)-targeted near-infrared conjugate (OTL78) to identify pulmonary squamous cell carcinoma. We identified PSMA as a viable target by examining its expression in human lung tumor specimens from a surgical cohort. Ninety-four percent of tumors expressed PSMA in either the pulmonary squamous cells or the tumor neovasculature. Using in vitro and in vivo models, we found that OTL78 reliably localized pulmonary squamous cell carcinoma in a PSMA-dependent manner. Finally, we found that IMI with OTL78 markedly improved surgeons' ability to identify residual disease after surgery in a preclinical model. Ultimately, this novel optical tracer may aid surgical resection of pulmonary squamous cell carcinoma and potentially improve long-term outcomes.

Combined legumain- and integrin-targeted nanobubbles for molecular ultrasound imaging of breast cancer

Molecular ultrasound imaging is a promising strategy for non-invasive and precise cancer diagnosis. Previously reported ultrasound contrast agents (UCAs) are mostly microbubbles or nanobubbles (NBs) larger than 200 nm, leading to less efficient tumor delivery. Here we synthesized NBs with a small size (~49 nm) and modified the NB surface with alanine-alanine-asparagine (NB-A) or arginine-glycine-aspartic acid peptide (NB-R) for concurrent active targeting towards legumain in tumor cells and integrin in tumor neovasculature. In vitro, the NB-A and NB-R presented echogenicity comparable with SonoVue MBs and showed specific binding with tumors cells and endothelial cells, respectively. In vivo, the combined NB-A/NB-R accumulated in tumor tissues selectively and provided ultrasound signals with prolonged duration and that were significantly stronger than non-targeted NBs, single-targeted NBs and SonoVue MBs. Overall, the dual targeted NBs served as efficient UCAs for specific imaging of breast cancer, and hold great potential for general cancer diagnosis/monitoring in the future.

CT imaging findings of renal epithelioid lipid-poor angiomyolipoma.

To identify specific imaging and clinicopathological features of a rare potentially malignant epithelioid variant of renal lipid-poor angiomyolipoma (E-lpAML). A total of 20 patients with E-lpAML and 43 patients with other lpAML were retrospectively included. Multiphase computed tomography (CT) imaging features and clinicopathological findings were recorded. Independent predictors for E-lpAML were identified using multivariate logistic regression and were used to construct a diagnostic score for differentiation of E-lpAML from other lpAML. The E-lpAML group consisted of 6 men and 14 women (age median ± SD: 39.45 ± 15.70, range: 16.0-68.0years). E-lpAML tended to appear as hyperdense mass lesions located at the renal sinus (n = 8, 40%) or at the renal cortex (n = 12, 60%), with a "fast-in and slow-out" enhancement pattern (n = 20, 100%), cystic degeneration (n = 18, 90%), "eyeball" sign (n = 11, 55%), and tumor neo-vasculature (n = 15, 75%) on CT. Multivariate logistic regression analysis showed that the independent predictors for diagnosing E-lpAML were cystic degeneration on CT imaging and CT value of the tumor in corticomedullary phase of enhancement. A predictive model was built with the two predictors, achieving an area under the curve (AUC) of 93.5% (95% confidence interval (95%CI): 84.3-98.2%) with a sensitivity of 95.0% (95%CI: 75.1-99.9%) and a specificity of 83.72% (95%CI: 69.3-93.2%). We identified specific CT imaging features and predictors that could contribute to the correct diagnosis of E-lpAML. Our findings should be helpful for clinical management of E-lpAML which could potentially be malignant and may require nephron-sparing surgery while other lpAML tumors which are benign require no intervention. • It is important to differentiate renal epithelioid lipid-poor angiomyolipoma (E-lpAML) from other lpAML because of differences in clinical management. • E-lpAML tumors tend to be large hyperdense tumors in the renal sinus with cystic degeneration and "fast-in and slow-out" pattern of enhancement. • Our CT imaging-based predictive model was robust in its performance for predicting E-lpAML from other lpAML tumors.

Non-Cationic RGD-Containing Protein Nanocarrier for Tumor-Targeted siRNA Delivery.

Despite the recent successes in siRNA therapeutics, targeted delivery beyond the liver remains the major hurdle for the widespread application of siRNA in vivo. Current cationic liposome or polymer-based delivery agents are restricted to the liver and suffer from off-target effects, poor clearance, low serum stability, and high toxicity. In this study, we genetically engineered a non-cationic non-viral tumor-targeted universal siRNA nanocarrier (MW 26 KDa). This protein nanocarrier consists of three function domains: a dsRNA binding domain (dsRBD) (from human protein kinase R) for any siRNA binding, 18-histidine for endosome escape, and two RGD peptides at the N- and C-termini for targeting tumor and tumor neovasculature. We showed that cloned dual-RGD-dsRBD-18his (dual-RGD) protein protects siRNA against RNases, induces effective siRNA endosomal escape, specifically targets integrin αvβ3 expressing cells in vitro, and homes siRNA to tumors in vivo. The delivered siRNA leads to target gene knockdown in the cell lines and tumor xenografts with low toxicity. This multifunctional and biomimetic siRNA carrier is biodegradable, has low toxicity, is suitable for mass production by fermentation, and is serum stable, holding great potential to provide a widely applicable siRNA carrier for tumor-targeted siRNA delivery.

Curcumin: A Systematic Review

Many pharmacologically active compounds can be found in medicinal plants. Phytochemicals are currently being studied by scientists to treat a variety of human illnesses. Turmeric (Curcuma longa), a rhizomatous perennial plant in the Zingiberaceae family, is widely used as a food ingredient and in traditional medicine to cure a variety of diseases. Anti-inflammatory, antifungal, anti-angiogenesis, virucidal, anti-mutagenic, and antioxidant activities are all present in it. Angiogenesis, or the formation of new blood vessels, is an important homeostatic mechanism that controls vascular populations in response to physiological and pathological demands, such as chronic inflammation and cancer. Curcumin, a natural polyphenol compound has an activity to inhibit angiogenesis by suppressing tumor neovasculature formation. This study aims to investigate the anti-angiogenesis effect of curcumin.

P11.02 Targeting the Tumor Neovasculature in Lung Cancer: A Phase I Study of AMG 160 in Subjects With Non-Small Cell Lung Cancer

Despite recent therapeutic advances, patients with relapsed/refractory non-small cell lung cancer (R/R NSCLC) have a dismal prognosis and there is an unmet need for more effective treatment options. AMG 160 is a half-life extended (HLE) BiTE® (bispecific T-cell engager) molecule that simultaneously binds prostate specific membrane antigen (PSMA) on tumor cells and CD3 on T cells to drive T cell-mediated lysis of tumors. The encouraging benefit-risk profile observed in an ongoing trial of AMG 160 in patients with metastatic castration-resistant prostate cancer (mCRPC) (NCT03792841) suggests a potential application for AMG 160 in patients with other PSMA-expressing tumors.

Preparation and Characterization of Targeted Microbubbles.

Targeting of microbubbles (ultrasound contrast agents for molecular imaging) has been researched for more than two decades. However, methods of microbubble preparation and targeting ligand attachment are cumbersome, complicated, and lengthy. Therefore, there is a need to simplify the targeted microbubble preparation procedure to bring it closer to clinical translation. The purpose of this publication is to provide a detailed description and explanation of the steps necessary for targeted microbubble preparation, functional characterization and testing. A sequence of the optimized and simplified procedures is presented for two systems: a biotin-streptavidin targeting pair model, and a cyclic RGD peptide targeting the recombinant αvβ3 protein, which is overexpressed on the endothelial lining of the tumor neovasculature. Here, we show the following: covalent coupling of the targeting ligand to a lipid anchor, assessment of the reagent quality, and tests that confirm the successful completion of the reaction; preparation of the aqueous precursor medium containing microbubble shell components, followed by microbubble preparation via amalgamation; assessment of the efficacy of lipid transfer onto the microbubble stabilizer shell; adjustment of microbubble size distribution by flotation at normal gravity to remove larger microbubbles that might be detrimental for in vivo use; assessment of microbubble size distribution by electrozone sensing; evaluation of targeted binding of the microbubbles to receptor-coated surface in a static binding assay test (in an inverted dish); and evaluation of targeted binding of the microbubbles to receptor-coated surface in a parallel plate flow chamber test.

Possible diagnostic pitfalls in 68Ga-PSMA PET/CT interpretation

Introduction/Aim 68 Ga-PSMA PET/CT is increasingly used in the evaluation of prostate cancer (PC), particularly in the detection and localization of disease recurrence. The main aim of the current study is to present physiological variation in distribution of PSMA activity and avidity in various benign and neoplastic conditions, as well as false-negative findings that may be misinterpreted. Materials and Methods PSMA represents an excellent biological target for high quality PET imaging of PC. However, PSMA uptake is not prostate-specific and is also expressed in other pathologic conditions. The causes of false-positive and false-negative 68 Ga-PSMA PET/CT findings are described. It is important for reporting physicians to recognize these findings. Results and Discussion PSMA is expressed in various benign and pathologic conditions. A wide range of malignancies other than PC have been reported to express PSMA as part of tumor neovasculature. Conclusion The nonexclusivity of PSMA avidity can potentially pave the way to expand the PSMA theranostic concept outside of PC.

An antibody-based enzymatic therapy for cancer treatment: The selective localization of D-amino acid oxidase to EDA fibronectin

In order to generate an antibody directed enzyme prodrug therapy, here we designed a chimeric protein by fusing the F8 antibody that recognizes the EDA of fibronectin (expressed on the tumor neovasculature) and an evolved variant of the ROS-generating enzyme D-amino acid oxidase (DAAO). The F8(scFv)-DAAO-Q144R recombinant protein is expressed by both CHO-S and E. coli cells. The F8(scFv)-DAAO-Q144R from E. coli cells is fully soluble, shows a high specific activity, is more thermostable in blood than the native DAAO, possesses a binding affinity for EDA well suited for efficient tumor accumulation, and localizes in tumor tissues. Notably, the F8(scFv)-DAAO-Q144R conjugate generates a stronger cytotoxicity to tumor cells than the native enzyme, especially when an inhibitor of heme oxygenase-1 (HO-1) is used, making it a promising candidate for a selective antitumor oxidative therapy controlled by the substrate addition, in the so called “activity on demand”, thus sparing normal tissue from damage.

Spotlight on PSMA as a new theranostic biomarker for bladder cancer

Bladder cancer (BCa) patients are diagnosed by cytology and cystoscopy. However, these diagnostic tests bear some limitations. We sought for reliable biomarkers to better determine BCa extension. Prostate-specific membrane antigen (PSMA) appears to fulfill this requirement in prostate cancer but its role in BCa has not been established yet. We then analyzed 87 bladder tissue samples from 74 patients assessing PSMA expression by immunohistochemistry. The median PSMA expression, exclusively found in tumor neovasculature, in terms of H-score significantly differed between non-tumor samples and tumor samples (p = 0.00288) showing a higher neovasculature-related PSMA expression. No differences were observed in relation to tumor type, grade and stage. BCa neovasculature-related PSMA overexpression may be useful in defining the degree of extension of the neoplasm. In addition, testing PSMA expression by immunohistochemistry may hold theranostic implications both considering anti-angiogenesis agents and radio-labelled PSMA ligands for intracavitary radionuclide therapy. In our opinion, BCa neovasculature-related PSMA overexpression may be considered an apt target for anti-angiogenesis and radionuclide treatment in BCa, once the evaluation of tumor-retention time for the appropriateness of long half-life therapeutic PSMA ligands as radionuclide treatment will be performed.