Αvβ3 Integrin Receptor Research Articles

PKCα Activation via the Thyroid Hormone Membrane Receptor Is Key to Thyroid Cancer Growth

Thyroid carcinoma (TC) is the most common endocrine neoplasia, with its incidence increasing in the last 40 years worldwide. The determination of genetic and/or protein markers for thyroid carcinoma could increase diagnostic precision. Accumulated evidence shows that Protein kinase C alpha (PKCα) contributes to tumorigenesis and therapy resistance in cancer. However, the role of PKCα in TC remains poorly studied. Our group and others have demonstrated that PKCs can mediate the proliferative effects of thyroid hormones (THs) through their membrane receptor, the integrin αvβ3, in several cancer types. We found that PKCα is overexpressed in TC cell lines, and it also appeared as the predominant expressed isoform in public databases of TC patients. PKCα-depleted cells significantly reduced THs-induced proliferation, mediated by the integrin αvβ3 receptor, through AKT and Erk activation. In databases of TC patients, higher PKCα expression was associated with lower overall survival. Further analyses showed a positive correlation between PKCα and genes from the MAPK and PI3K-Akt pathways. Finally, immunohistochemical analysis showed abnormal upregulation of PKCα in human thyroid tumors. Our findings establish a potential role for PKCα in the control of hormone-induced proliferation that can be explored as a therapeutic and/or diagnostic target for TC.

Effect and mechanism of Adipokine Omentin-1 on cardiac hypertrophy in heart failure with preserved ejection fraction

Abstract Background Omentin-1 secreted by epicardial adipose tissue can inhibit ventricular remodeling and improve early cardiac function after myocardial infarction. Our previous studies have identified the omentin-1 receptor as integrin receptors αvβ3 and αvβ5. However, the effect of omentin-1 on heart failure with preserved ejection fraction (HFpEF) remains poorly understood. Purpose The present study aims to study the role and mechanism of omentin-1 in cardiac function and myocardial cell structure in HFpEF. Methods and Results The influences of omentin-1 were investigated in HFpEF mice (HFD (60% calories from lard) and L-NAME (0.5 g/L in drinking water)), which were treated in vivo. Echocardiography showed better diastolic function in HFpEF mice treated with omentin-1 (5 ug/kg/h) subcutaneously for 4 weeks, and tissue staining showed alleviated myocardial fibrosis and myocardial hypertrophy. The RNA sequencing analysis revealed variations in the gene expression related to ketone body metabolism in HFpEF mice after omentin-1 treatment (600 ng/ml). The supernatant was obtained from mouse bone marrow macrophages treated with ultrapure endotoxin and ATP and was utilized as the macrophage-conditioned medium for culturing primary cardiomyocytes, which were stimulated with isoproterenol for 48 hours to construct the HFpEF cardiomyocyte model. In the heart tissue of HFpEF mice and HFpEF cardiomyocytes treated with omentin-1, there was a notable increase in the expression of a pivotal enzyme of ketone body metabolism- succinyl-CoA transferase (SCOT), and a decrease in the expression of hypertrophy signal. The myocardial hypertrophy model was established by stimulating the myocardial cell line H9C2 with isoproterenol. Following the inhibition of the integrin receptor and PI3K-AKT pathway, the impacts of omentin-1 on SCOT and myocardial hypertrophy signal expression in hypertrophic cardiomyocytes were eliminated. Conclusion This study provides evidence for the effects of omentin-1 on cardiac function and myocardial structure in HFpEF and proposes that omentin-1 may stimulate the downstream PI3K/AKT pathway via integrin receptors on cardiomyocytes, leading to increased expression of SCOT and improvement of cardiomyocyte hypertrophy.

Preventing osteoporotic bone loss in mice by promoting balanced bone remodeling through M-CSFRGD, a dual antagonist to c-FMS and αvβ3 receptors

Osteoporosis is a common, age-related disease caused by imbalanced bone remodeling. Current treatments either shut down bone resorption or robustly stimulate bone formation. Here, we describe a novel compound that inhibits osteoclast activity without causing apparent disruptions to bone formation by targeting both c-FMS (i.e., osteoclast differentiation) and αvβ3 integrin (i.e., osteoclastic bone resorption) receptors. We show that human serum albumin (HSA)-conjugated M-CSFRGD protein (M-CSFRGD-HSA) effectively inhibits the activity of both receptors, with a three-fold higher serum half-life compared to the unconjugated M-CSFRGD. We then treated ovariectomized mice with different doses of M-CSFRGD-HSA, alendronate, or a monospecific control protein. The bispecific M-CSFRGD-HSA was superior to a monospecific control in alleviating bone loss and reducing osteoclast distribution and function. M-CSFRGD-HSA and alendronate effectively prevented ovariectomy-induced bone loss, but M-CSFRGD-HSA had a milder inhibitory effect on osteoclast distribution and activity. Moreover, alendronate halted bone formation, while M-CSFRGD-HSA-treated mice showed an increased level of serum amino-terminal propeptide of type I collagen, a bone formation marker. Our data indicate that the mild reduction in osteoclast activity facilitated by the bispecific M-CSFRGD-HSA allows the maintenance of certain levels of bone formation and may be superior to treatments that induce osteoclast depletion.

A near-infrared fluorescent probe with assembly/aggregation-induced retention effect for specific diagnosis of metastasis and image-guided surgery in breast cancer

Image-guided surgery is crucial for achieving complete tumor resection, reducing postoperative recurrence and improving patient survival. However, current clinical near-infrared fluorescent probes, such as indocyanine green (ICG), face two main limitations: 1) lack of active tumor targeting, and 2) short retention time in tumors, which restricts real-time imaging during surgery. To address these issues, we developed a near-infrared fluorescent probe capable of in situ nanofiber formation within tumor lesions. This probe actively targets the integrin αvβ3 receptors overexpressed on breast cancer cells and exhibits assembly/aggregation-induced retention effects at the tumor site, significantly extending the imaging time window. Additionally, we found that the probe's fluorescence intensity can be enhanced under receptor induction. Due to its excellent tumor specificity and sensitivity, 1FCG-FFGRGD not only identifies primary breast cancer but also precisely locates smaller lymph node metastases and detects sub-millimeter peritoneal metastases. In summary, this near-infrared probe, leveraging assembly/aggregation-induced retention effects, holds substantial potential for various biomedical applications.

Peptide-functionalized gold nanoparticles for boron neutron capture therapy with the potential to use in Glioblastoma treatment

Glioblastoma is a highly aggressive glioma with limited treatment options. Boron neutron capture therapy (BNCT) offers a promising approach for refractory cancers, utilizing boron-10 (10B) and thermal neutrons to generate cytotoxic particles. Effective BNCT depends on selective targeting and retention of 10B in tumors. Current BNCT drugs face issues with rapid clearance and poor tumor accumulation. To address this, we developed gold nanoparticles (AuNPs) functionalized with cyclic arginine-glycine-aspartic acid (cRGD) peptides as a nanocarrier for Sodium Mercaptododecaborate (BSH), resulting in AuNPs-BSH&PEG-cRGD. In vitro, AuNPs-BSH&PEG-cRGD increased 10B content in GL261 glioma cells by approximately 2.5-fold compared to unmodified AuNPs-BSH&PEG, indicating enhanced targeting due to cRGD's affinity for integrin receptor αvβ3. In a subcutaneous glioma mouse model, 6 h post-intratumoral administration, the 10B concentration in tumors was 17.98 μg/g for AuNPs-BSH&PEG-cRGD, significantly higher than 0.45 μg/g for BSH. The tumor-to-blood (T/B) and tumor-to-normal tissue (T/N) ratios were also higher for AuNPs-BSH&PEG-cRGD, suggesting improved targeting and retention. This indicates that AuNPs-BSH&PEG-cRGD may enhance BNCT efficacy and minimize normal tissue toxicity. In summary, this study provides a novel strategy for BSH delivery and may broaden the design vision of BNCT nano-boron capture agents.

Bone sialoprotein stimulates cancer cell adhesion through the RGD motif and the αvβ3 and αvβ5 integrin receptors.

Being implicated in bone metastasis development, bone sialoprotein (BSP) expression is upregulated in patients with cancer. While BSP regulates cancer cell adhesion to the extracellular matrix, to the best of our knowledge, the specific adhesive molecular interactions in metastatic bone disease remain unclear. The present study aimed to improve the understanding of the arginine-glycine-aspartic acid (RGD) sequence of BSP and the integrin receptors αvβ3 and αvβ5 in BSP-mediated cancer cell adhesion. Human breast cancer (MDA-MB-231), prostate cancer (PC-3) and non-small cell lung cancer (NSCLC; NCI-H460) cell lines were cultured on BSP-coated plates. Adhesion assays with varying BSP concentrations were performed to evaluate the effect of exogenous glycine-arginine-glycine-aspartic acid-serine-proline (GRGDSP) peptide and anti-integrin antibodies on the attachment of cancer cells to BSP. Cell attachment was assessed using the alamarBlue® assay. The present results indicated that BSP supported the adhesion of cancer cells. The RGD counterpart GRGDSP peptide reduced the attachment of all tested cancer cell lines to BSP by ≤98.4%. Experiments with anti-integrin antibodies demonstrated differences among integrin receptors and cancer cell types. The αvβ5 antibody decreased NSCLC cell adhesion to BSP by 84.3%, while the αvβ3 antibody decreased adhesion by 14%. The αvβ3 antibody decreased PC-3 cell adhesion to BSP by 46.4%, while the αvβ5 antibody decreased adhesion by 9.5%. Adhesion of MDA-MB-231 cells to BSP was inhibited by 54.7% with αvβ5 antibody. The present results demonstrated that BSP-induced cancer cell adhesion occurs through the binding of the RGD sequence of BSP to the cell integrin receptors αvβ3 and αvβ5. Differences between cancer types were found regarding the mediation via αvβ3 or αvβ5 receptors. The present findings may explain why certain cancer cells preferentially spread to the bone tissue, suggesting that targeting the RGD-integrin binding interaction could be a promising novel cancer treatment option.

Design of an Acidic pH-Activated NIR Fluorescent Convertible Rhodamine-Hemicyanine Probe-Peptide Conjugate for Living Cancer Cell Active Targeted Selective Tracking of Lysosomes.

We have synthesized an acidic pH-activatable dual targeting ratiometric fluorescent probe-peptide conjugate using the SPPS protocol on Rink amide AM resin. Living carcinoma cell specific active targeting, successive cell penetration, and selective staining of lysosomes are accomplished. Real-time monitoring of lysosomes, 3D, and multicolor cancer cell imaging are also attained. The de novo design consists of the integration of multifunctionality into a single molecular scaffold, e. g., RGDS peptide residue to target cancer cell surface overexpressed receptor αVβ3 integrin, live-cell penetrating organic unsymmetrical rhodamine-hemicyanine chromophore comprising a lysosome targeting morpholine group, and an acidic pH openable spiro-lactam ring for a visible-to-NIR switchable ratiometric response. Water-soluble fluorescent probe-peptide conjugate exhibits intramolecular spirolactamization at basic pH through Arg amide N. The visible spirolactam state predominantly exists at physiological and basic pH and can be switched to the highly conjugated NIR open amide state (λem=735 nm) through spiro-lactam ring opening triggered by acidic pH with a huge bathochromic shift (Δλabs=336 nm, ΔλFL=265 nm). Moreover, pH-sensitive ratiometric optical switching is achieved. This in situ acidic cancer cell lysosome activatable multifunctional fluorophore-peptide conjugate shows augmented molar absorptivity, enhanced quantum yield, and improved fluorescence lifetime at acidic lysosomal pH; negligible cytotoxicity; and dual targeted ratiometric imaging capability of living cancer cell selective lysosomes with a pKa value of 5.1.

Renal Clearable H‐Dots Leveraging Ligand Complexation for Enhanced Active Tumor Targeting

The use of ligand conjugation onto nanoparticle surfaces as an active targeting strategy has gained significant attention in the pursuit of improving tumor‐specific delivery and retention. However, the chemical conjugation of targeting moieties often induces alterations in the physicochemical properties of nanoparticles, including size, conformation, charge‐to‐mass ratio, and hydrophilicity/lipophilicity, resulting in unexpected biodistribution and pharmacokinetic profiles. Here, the enhanced active targeting efficiency achieved by integrating cyclic arginine–glycine–aspartic acid (cRGD) peptides onto ultrasmall nanocarrier H‐dot while preserving its essential physicochemical and pharmacokinetic attributes is investigated. The resulting cRGD/H‐dots demonstrate improved cellular uptake via integrin αvβ3 receptors, accompanied by negligible cytotoxicity. Notably, the active targeting efficacy of cRGD/H‐dots compared to unmodified H‐dots (1.2%ID/g, two‐fold increase) is quantitatively evaluated, validated through fluorescence imaging and histological analysis. The findings highlight that cRGD/H‐dots offer enhanced tumor targetability and prolonged tumoral retention while maintaining active renal clearance of unbound molecules.

Near-infrared pH-switchable BODIPY photosensitizers for dual biotin/cRGD targeted photodynamic therapy

Photodynamic therapy (PDT) is a clinically-approved cancer treatment that is based on production of cytotoxic reactive oxygen species to induce cell death. However, its efficiency depends on distribution of photosensitizer (PS) and depth of light penetration through the tissues. Tendency of pathological cancer tissues to exhibit lower pH than healthy tissues inspired us to explore dual-targeted pH-activatable photosensitizers based on tunable near-infrared (NIR) boron-dipyrromethene (BODIPY) dyes. Our BODIPY PSs were designed to carry three main attributes: (i) biotin or cRGD peptide as an effective cancer cell targeting unit, (ii) amino moiety that is protonated in acidic (pH <6.5) conditions for pH-activation of the PS based on photoinduced electron transfer (PET) and (iii) hydrophilic groups enhancing the water solubility of very hydrophobic BODIPY dyes. Illumination of such compounds with suitable light (>640nm) allowed for high phototoxicity against HeLa (αvβ3 integrin and biotin receptor positive) and A549 (biotin receptor positive) cells compared to healthy MRC-5 (biotin negative) cells. Moreover, no dark toxicity was observed on selected cell lines (>10 μM) providing promising photosensitizers for tumour-targeted photodynamic therapy.

Thyroid hormone T3 induces Fyn modification and modulates palmitoyltransferase gene expression through αvβ3 integrin receptor in PC12 cells during hypoxia.

Thyroid hormones (THs) are essential in neuronal and glial cell development and differentiation, synaptogenesis, and myelin sheath formation. In addition to nuclear receptors, TH acts through αvβ3-integrin on the plasma membrane, influencing transcriptional regulation of signaling proteins that, in turn, affect adhesion and survival of nerve cells in various neurologic disorders. TH exhibits protective properties during brain hypoxia; however, precise intracellular mechanisms responsible for the preventive effects of TH remain unclear. In this study, we investigated the impact of TH on integrin αvβ3-dependent downstream systems in normoxic and hypoxic conditions of pheochromocytoma PC12 cells. Our findings reveal that triiodothyronine (T3), acting through αvβ3-integrin, induces activation of the JAK2/STAT5 pathway and suppression of the SHP2 in hypoxic PC12 cells. This activation correlates with the downregulation of the expression palmitoyltransferase-ZDHHC2 and ZDHHC9 genes, leading to a subsequent decrease in palmitoylation and phosphorylation of Fyn tyrosine kinase. We propose that these changes may occur due to STAT5-dependent epigenetic silencing of the palmitoyltransferase gene, which in turn reduces palmitoylation/phosphorylation of Fyn with a subsequent increase in the survival of cells. In summary, our study provides the first evidence demonstrating the involvement of integrin-dependent JAK/STAT pathway, SHP2 suppression, and altered post-translational modification of Fyn in protective effects of T3 during hypoxia.

Milk Fat Globule-EGF Factor 8 (MFGE8) Mitigates Cognitive Impairment in Rats with Sepsis-Associated Encephalopathy: An fMRI Study.

Sepsis-associated encephalopathy (SAE) impairs hippocampal microglial efferocytosis, causing cognitive deficits. Previous research found that milk fat globule epidermal growth factor 8 protein (MFGE8) stimulates efferocytosis, reducing hippocampal inflammation in SAE rats. In this study, we explore MFGE8's role in alleviating cognitive impairment and its impact on neural activity using functional magnetic resonance imaging (fMRI). Sixty male Sprague Dawley rats were divided into four groups: Sham, cecal ligation and puncture (CLP), CLP+MFGE8, and CLP+MFGE8+CGT (Cilengitide). After CLP, CLP+MFGE8 rats received intracerebroventricular MFGE8 (3.3 µg), while CLP+MFGE8+CGT rats received intraperitoneal Cilengitide (10 mg/kg). We assessed cognitive function with the Morris water maze and open field test over five days. Eight days post-surgery, rats underwent T2-weighted magnetic resonance imaging (MRI) and resting state (rs)-fMRI scans. Brain tissues were collected for western blot, hematoxylin-eosin (HE) staining, and immunofluorescence. Statistical analysis employed one-way analysis of variance (ANOVA) followed by Tukey's post-test for multiple comparisons. MFGE8 improved neurobehavioral performance in open field task (OFT) and morris water maze (MWM) tests. fMRI indicated a significant reduction in abnormal neural activity in the right hippocampal CA1, CA3, and dentate gyrus of SAE rats following MFGE8 treatment. Voxel-based morphometry (VBM) analysis revealed decreased high-signal areas in the hippocampus, along with reduced hippocampal volume due to alleviated neural edema. Western blot analysis demonstrated that MFGE8 enhanced ras-related C3 botulinum toxin substrate 1 (Rac1) and microtubule-associated protein 1A/1B-light chain 3 (LC3) expression in the rat hippocampus, while CGT reduced these protein levels. Behavioral experiments and fMRI results confirmed that CGT reversed the cognitive effects of MFGE8 by inhibiting microglial αVβ3/αVβ5 integrin receptors. Our findings show that MFGE8 reduced amplitude of low-frequency fluctuations (ALFF) values in the right hippocampal CA1, CA3, and the dentate gyrus, mitigating abnormal neural activity and decreasing hippocampal volume. This led to an improvement in cognitive dysfunction in SAE rats. These results suggest that MFGE8 enhances microglial efferocytosis by activating αVβ3 and αVβ5 integrin receptors on microglial surfaces, ultimately improving cognitive function in SAE rats.

Engineering Tumor‐Specific Nanotheranostic Agent with MR Image‐Guided NIR‐II &amp; ‐III Photodynamic Therapy to Combat Against Deeply Seated Orthotopic Glioblastoma

Glioblastoma multiforme (GBM) is one of the most aggressive, incurable, and difficult‐to‐treat malignant brain tumor with very poor survival rates. The gold standard in treating GBMs includes neurosurgical resection of the tumor, followed by the chemotherapy and radiotherapy. However, these strategies remain ineffective in treating patients with GBMs, as tumor recurrence always occur in most cases. Therefore, it remains a grand challenge to develop an effective strategy to combat orthotopic glioblastoma with simultaneous imaging capabilities to monitor the therapeutic outcomes. To tackle this challenge, this study demonstrates, for the first time, that a tumor‐specific europium hexaboride (EuB6)‐based nanomedicine surface‐modified with RGD‐K peptide to target αvβ3 integrin receptors overexpressed on the glioblastoma cells. Further, EuB6@RGD‐K NPs are able to exert theranostic capabilities to effectively diagnose and combat difficult‐to‐treat orthotopic glioblastoma tumors using NIR‐II 1064 nm and NIR‐III 1550 nm photodynamic therapy (NIR PDT) effects. In the in vivo experiments, the average half‐life of 55 d for mice treated with EuB6@RGD‐K NPs and exposed to NIR‐III 1550 nm light irradiation is far higher than that of EuB6@RGD‐K NPs exposed to NIR‐II 1064 nm light irradiation (25 d), PBS‐treated mice (20 d) and EuB6@RGD‐K NPs‐treated mice (no light irradiation, 18 d). To the best of our knowledge, this work represents the first example for destructing murine brain tumors via multi‐functional tumor‐specific europium hexaboride‐based nanotheranostic agent to mediate MR imaging‐guided NIR‐II/‐III photodynamic therapy.

Tuning of Ultrasmall Gold Nanoparticles Surface Properties Affect Their Biological Fate

AbstractUltrasmall nanoparticles of 10 nm or less in size have been shown to have great potential in the biomedical field due to their high surface area and strong tissue penetration. Their easy functionalization and unique behavior at the nanoscale, such as the reduced corona formation and lower liver retention allow them to be a potential tool for precision targeting. In this study, PEGylated ultrasmall gold nanoparticles (GNPs) with a 4 nm core size are developed. They are functionalized with the cyclic RGD (cRGD) targeting peptide, which provides high binding affinity toward αVβ3 integrin receptor, often overexpressed in solid tumors. Further evidence is presented that cRGD functionalized GNPs partially escape lysosomes while penetrating deeper into the liver parenchyma. These particles provide a potential future strategy for specific αVβ3 integrin targeting.

Anticancer Properties of Different Varieties of Date Palm (Phoenix dactylifera L.) Leaf Extracts in Human Tumor Cells: a Comparative Study.

Plant polyphenols are nutraceutical components with relevant biological effects on human health. They act against development of several diseases including cancer. In this study, the methanolic extracts of four date palm Phoenix dactylifera leaves (Deglet Noor (DN), Barhee (B), Khalas (KS) and Khunezi (KZ)) collected from south Tunisia were preliminary analyzed for their effects against U87 (human glioblastoma) and MDA-MB-231 (human breast cancer) cell line development. Results showed that Barhee extract (30μg/mL) was the most efficient to reduce the growth of both tumor cells to about 40% (p < 0.05) without inducing cytotoxicity. Significantly, KS, KZ, DN and B extracts (30μg/mL) decreased MDA-MB-231 and U87 cell adhesion towards fibrinogen and fibronectin. Using integrin blocking antibodies, leaf extracts competitively decreased human glioblastoma cell attachment to immobilized antibodies by interfering to αvβ3 and α5β1 integrin receptors. At the same concentration, extracts decreased MDA-MB-23 and U87 cell migration performed with wound healing assay. Particularly, Barhee and Deglet Noor leaf extracts (30μg/mL) significantly reduced U87 cell invasion by 52.92% (p < 0.01) and 74.56% (p < 0.01), respectively. Collegially, our findings revealed beneficial proprieties of four varieties of date palm leaf especially those displayed by DN and B extracts that may serve as active candidates against human glioblastoma and breast cancer progression.

Peptide-Directed Synthesis of Aggregation-Induced Emission Enhancement-Active Gold Nanoclusters for Single- and Two-Photon Imaging of Lysosome and Expressed αvβ3 Integrin Receptors.

This study explores the synthesis and characterization of aggregation-induced emission enhancement (AIEE)-active gold nanoclusters (AuNCs), focusing on their near-infrared luminescence properties and potential applications in biological imaging. These AIEE-active AuNCs were synthesized via the NaBH4-mediated reduction of HAuCl4 in the presence of peptides. We systematically investigated the influence of the peptide sequence on the optical features of the AuNCs, highlighting the role of glutamic acid in enhancing their quantum yield (QY). Among the synthesized peptide-stabilized AuNCs, EECEE-stabilized AuNCs exhibited the maximum QY and a pronounced AIEE effect at pH 5.0, making them suitable for the luminescence imaging of intracellular lysosomes. The AIEE characteristic of the EECEE-stabilized AuNCs was demonstrated through examinations using transmission electron microscopy, dynamic light scattering, zeta potential analysis, and single-particle imaging. The formation of the EECEE-stabilized AuNCs was confirmed by size-exclusion chromatography and mass spectrometry. Spectroscopic and electrochemical examinations uncover the formation process of EECEE-stabilized AuNCs, comprising EECEE-mediated reduction, NaBH4-induced nucleation, complex aggregation, and subsequent cluster growth. Furthermore, we demonstrated the utility of these AuNCs as luminescent probes for intracellular lysosomal imaging, leveraging their pH-responsive AIEE behavior. Additionally, cyclic arginylglycylaspartic acid (RGD)-modified AIEE dots, derived from cyclic RGD-linked peptide-induced aggregation of EECEE-stabilized AuNCs, were developed for single- and two-photon luminescence imaging of αvβ3 integrin receptor-positive cancer cells.

Development of 5-Fluorouracil/pH-Responsive Adjuvant-Embedded Extracellular Vesicles for Targeting αvβ3 Integrin Receptors in Tumors.

To selectively target and treat murine melanoma B16BL6 tumors expressing αvβ3 integrin receptors, we engineered tumor-specific functional extracellular vesicles (EVs) tailored for the targeted delivery of antitumor drugs. This objective was achieved through the incorporation of a pH-responsive adjuvant, cyclic arginine-glycine-aspartic acid peptide (cRGD, serving as a tumor-targeting ligand), and 5-fluorouracil (5-FU, employed as a model antitumor drug). The pH-responsive adjuvant, essential for modulating drug release, was synthesized by chemically conjugating 3-(diethylamino)propylamine (DEAP) to deoxycholic acid (DOCA, a lipophilic substance capable of integrating into EVs' membranes), denoted as DEAP-DOCA. The DOCA, preactivated using N-(2-aminoethyl)maleimide (AEM), was chemically coupled with the thiol group of the cRGD-DOCA through the thiol-maleimide click reaction, resulting in the formation of cRGD-DOCA. Subsequently, DEAP-DOCA, cRGD-DOCA, and 5-FU were efficiently incorporated into EVs using a sonication method. The resulting tumor-targeting EVs, expressing cRGD ligands, demonstrated enhanced in vitro/in vivo cellular uptake specifically for B16BL6 tumors expressing αvβ3 integrin receptors. The ionization characteristics of the DEAP in DEAP-DOCA induced destabilization of the EVs membrane at pH 6.5 through protonation of the DEAP substance, thereby expediting 5-FU release. Consequently, an improvement in the in vivo antitumor efficacy was observed for B16BL6 tumors. Based on these comprehensive in vitro/in vivo findings, we anticipate that this EV system holds substantial promise as an exceptionally effective platform for antitumor therapeutic delivery.

Targeted treatment of chondrosarcoma with a bacteriophage-based particle delivering a secreted tumor necrosis factor-related apoptosis-inducing ligand

Chondrosarcoma is a malignant cartilage-forming bone tumor which is inherently resistant to chemotherapy and radiotherapy leaving surgery as the only treatment option. We have designed a tumor-targeted bacteriophage (phage)-derived particle (PDP), for targeted systemic delivery of cytokine-encoding transgenes to solid tumors. Phage has no intrinsic tropism for mammalian cells; therefore, it was engineered to display a double cyclic RGD4C ligand on the capsid to target tumors. To induce cancer cell death, we constructed a transgene cassette expressing a secreted form of the cytokine tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL). We detected high expression of αvβ3 and αvβ5 integrin receptors of the RGD4C ligand, and of the TRAIL receptor-2 in human chondrosarcoma cells (SW1353) but not in primary normal chondrocytes. The RGD4C.PDP-Luc particle carrying a luciferase reporter gene, Luc, effectively and selectively mediated gene delivery to SW1353 cells but not primary chondrocytes. Transduction of SW1353 cells with RGD4C.PDP-sTRAIL encoding a human sTRAIL, resulted in expression of TRAIL and subsequent cell dead without harming the normal chondrocytes. Intravenous administration of RGD4C.PDP-sTRAIL to mice with established human chondrosarcoma resulted in reduction of tumor size and tumor viability. Altogether, RGD4C.PDP-sTRAIL can be used to target systemic treatment of chondrosarcoma with the sTRAIL.

Abstract 6038: Copper-67 based targeted radiotherapy primes immunologically cold PDAC for immunotherapy

Abstract Background and Purpose: Immune checkpoint therapy (ICT) has revolutionized cancer treatment however efficacy remains dismal for some cancers, including pancreatic cancers. Strategies to enhance immune responses include combining ICT with other existing cancer therapies. Targeted radiotherapy (TRT) uses a radiolabeled cancer-targeting vector, allowing for systematic delivery of specific radiation to all tumor sites while minimizing radiation exposure to healthy tissues. We propose Targeted Copper Theranostics (TCTs) as a TRT, utilizing copper-67 to irradiate and prime immunologically “cold” pancreatic adenocarcinoma (PDAC) and evaluate the efficacy of copper-67-based TRT-ICT combination therapy. Methods: We evaluated two tumor-targeting vectors conjugated to a sarcophagine macrobicyclic chelator (SAR), an antibody—5B1, targeting the PDAC-specific biomarker carbohydrate antigen-19-9 (CA19-9), and a peptide RGD, targeting the αvβ3 integrin receptor, which is highly expressed in some PDAC tumors. We administrated ~1.1 MBq of [64Cu]Cu-SAR-bisRGD (~0.1 μg) or [64Cu]Cu-SAR-5B1 (~10 μg) to FC1245 Ft2Ab PDAC (a murine PDAC cell line expressing CA19-9) tumor-bearing C57BL/6 mice and performed biodistribution studies at 1 and 4 h for [64Cu]Cu-SAR-bisRGD-injected mice and at 24 and 48 h for [64Cu]Cu-5B1-injected mice. [67Cu]Cu-SAR-bisRGD- and [67Cu]Cu-SAR-5B1-based dose escalation studies and the combination of a copper-67-based TRT and ICT were performed to evaluate therapeutic efficacy of copper-67-based TRT and potential synergistic effects of combination therapy. Results: Tumor uptake of [64Cu]Cu-SAR-bisRGD is ~5 %ID/g at 4h-post injection, and tumor uptake of [64Cu]Cu-SAR-5B1 is ~55 %ID/g 24h-post injection. In dose escalation studies, administration of ~11, 22, and 37 MBq of [67Cu]Cu-SAR-bisRGD (~1 μg) or administration of ~4, 11, 18 MBq of [67Cu]Cu-5B1(~150 μg) improved overall survival to 25 or 32 days respectively, compared to the control cohort (14 days). Based on weekly whole-blood analyses, no significant radiotoxicity was observed in mice receiving various doses of TRTs. The combination of 11 MBq of either [67Cu]Cu-SAR-bisRGD or [67Cu]Cu-SAR-5B1 in combination with either antiPD-L1/PD1 or antiCTLA4, improved overall survival by ~7 days compared to ICT-treated control groups. Conclusion: Biodistribution studies demonstrated relatively high tumor specific uptake for [64Cu]Cu-SAR-bisRGD and [64Cu]Cu-SAR-5B1. Dose escalation study results suggest copper-67-based TRT could effectively inhibit tumor growth with minimal radiotoxicity. The combination of TRT with ICTs improved overall survival compared to single-ICT-treated control groups. Collectively, our results strongly support the hypothesis that TRT with [67Cu]Cu-SAR-bisRGD or [67Cu]Cu-SAR-5B1 could prime immunologically “cold” pancreatic adenocarcinoma (PDAC) to be responsive to ICTs. Citation Format: Yi Rao, Tara Viray, Kurt Gehlsen, Matt Harris, Lachlan McInnes, Olufolake Majekodunmi, Jason Lewis. Copper-67 based targeted radiotherapy primes immunologically cold PDAC for immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6038.

Association between thyroid disorders and extra-thyroidal cancers, a review.

Thyroid hormone has been shown to have both tumor-promoting and tumor-suppressing actions, which has led to significant debate over its involvement in the development of cancer. Proliferation, apoptosis, invasiveness, and angiogenesis are all aspects of cancer that are affected by the thyroid hormones T3 and T4, according to research conducted in animal models and in vitro experiments. The effects of thyroid hormones on cancer cells are mediated by many non-genomic mechanisms, one of which involves the activation of the plasma membrane receptor integrin αvβ3. Typically, abnormal amounts of thyroid hormones are linked to a higher occurrence of cancer. Both benign and malignant thyroid disorders were found to be associated with an increased risk of extra-thyroidal malignancies, specifically colon, breast, prostate, melanoma, and lung cancers. The purpose of this review was to shed light on this link to define which types of cancer are sensitive to thyroid hormones and, as a result, are anticipated to respond favorably to treatment of the thyroid hormone axis.

Integrin αvβ3 and LHRH Receptor Double Directed Nano-Analogue Effective Against Ovarian Cancer in Mice Model.

The high mortality rate of malignant ovarian cancer is attributed to the absence of effective early diagnosis methods. The LHRH receptor is specifically overexpressed in most ovarian cancers, and the integrin αvβ3 receptor is also overexpressed on the surface of ovarian cancer cells. In this study, we designed LHRH analogues (LHRHa)/RGD co-modified paclitaxel liposomes (LHRHa-RGD-LP-PTX) to target LHRH receptor-positive ovarian cancers more effectively and enhance the anti-ovarian cancer effects. LHRHa-RGD-LP-PTX liposomes were prepared using the thin film hydration method. The morphology, physicochemical properties, cellular uptake, and cell viability were assessed. Additionally, the cellular uptake mechanism of the modified liposomes was investigated using various endocytic inhibitors. The inhibitory effect of the formulations on tumor spheroids was observed under a microscope. The co-localization with lysosomes was visualized using confocal laser scanning microscopy (CLSM), and the in vivo tumor-targeting ability of the formulations was assessed using the IVIS fluorescent imaging system. Finally, the in vivo anti-tumor efficacy of the formulations was evaluated in the armpits of BALB/c nude mice. The results indicated that LHRHa-RGD-LP-PTX significantly enhanced cellular uptake in A2780 cells, increased cytotoxicity, and hand a more potent inhibitory effect on tumor spheroids of A2780 cells. It also showed enhanced co-localization with endosomes or lysosome in A2780 cells, improved tumor-targeting capability, and demonstrated an enhanced anti-tumor effect in LHRHR-positive ovarian cancers. The designed LHRHa-RGD-LP-PTX liposomes significantly enhanced the tumor-targeting ability and therapeutic efficacy for LHRH receptor-positive ovarian cancers.