Tumor-penetrating Peptide iRGD Research Articles

Abstract B055: Harnessing cytomegalovirus immunity against pancreatic tumors for immunotherapy

Abstract Immunotherapy has had very limited success in pancreatic cancer, due to its low mutational burden and immunosuppressive microenvironment. Our approach consists in redirecting pre- existing antiviral immunity against pancreatic tumors by delivering viral antigens using the tumor penetrating peptide iRGD .This peptide, targets the tumor vasculature through av integrins and neuropilin-1, delivering conjugated or co-administered cargo to tumors. Here we used mouse cytomegalovirus (CMV) as an infection model. CMV is a β-herpesvirus that induces a strong T-cell response in mice and humans, comprising >10% of all circulating CD4 and CD8 T cells mostly with effector-memory phenotype. Importantly, human CMV infects over 60% of the world’s population rendering it a suitable candidate for translation. Methods: Mice latently infected with CMV were orthotopically implanted with KPC pancreatic tumor cells and treated with systemic injections of vehicle or iRGD plus CMV class I and II binding peptides. Another cohort of age matched uninfected mice was used as a control. Tumor growth and mouse weight were monitored twice a week and CMV specific immune responses were measured in spleen, liver and tumor by flow cytometry, using tetramer staining and CMV specific peptide recall. Results: CMV infected mice receiving iRGD+CMV peptides responded to treatment as evidenced by delayed tumor growth associated with increased tumor necrosis and T cell infiltration. In addition, flow cytometry analysis of tumor, liver and spleen showed a significant increase in CMV specific T cells preferentially in the tumor. Surprisingly, these T cells preferentially infiltrated tumors regardless of the use of iRGD for tumor targeting of CMV peptides. Survival studies showed a marked increase in median survival, reaching 42 days in the infected and treated group, compared to 25 days in the vehicle treated one. The survival benefit was very similar in the presence or absence of iRGD. Combining this strategy with anti- PD1 and or anti-IL10R did not significantly improve the benefits of CMV therapy alone. On the other hand, combination with low dose gemcitabine (5mg/kg) significantly improved tumor growth delay and survival in the combination compared to either therapy alone. The median survival reached 49 days in the combination, compared to 39 for gemcitabine or CMV therapy alone and 32 for vehicle.Conclusions: We have recently performed single cell RNA sequencing in tumors from infected and CMV peptide or vehicle treated mice and will analyze the transcriptional profile and TCR sequence of the tumor infiltrating T cells. Preliminary analysis of this data shows a massive T cell infiltration and an increase in dendritic cells and macrophages in infected and treated mice. Taken together, this data shows we can deliver antigens to pancreatic tumors and elicit an anti-tumor immune response that results in delayed tumor growth and has a survival benefit. This is a mutation agnostic approach with high translational value, since more than 60% of the population has previous CMV immunity. Citation Format: Remi Marrocco, Jay Patel, Rithika Medari, Siming Sun, Kevin Gulay, Alexei Martsinkovskiy, Simon Brunel, Eduardo Lucero-Meza, Evangeline Mose, Andrew Lowy, Chris Benedict, Tatiana Hurtado de Mendoza. Harnessing cytomegalovirus immunity against pancreatic tumors for immunotherapy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B055.

Combining iRGD with HuFOLactis enhances antitumor potency by facilitating immune cell infiltration and activation

ABSTRACT Multiple research studies have demonstrated the efficacy of lactic acid bacteria in boosting both innate and adaptive immune responses. We have created a Lactococcus lactis variant that produces a modified combination protein with Fms-like tyrosine kinase 3 ligand and co-stimulator O × 40 ligand, known as HuFOLactis. The genetically modified variant was purposely created to activate T cells, NK cells, and DC cells in a laboratory setting. Furthermore, we explored the possibility of using the tumor-penetrating peptide iRGD to deliver HuFOLactis-activated immune cells to hard-to-reach tumor areas. Following brief stimulation with HuFOLactis, immune cell phenotypes and functions were assessed using flow cytometry. Confocal microscopy was employed to demonstrate the infiltrative and cytotoxic capabilities of iRGD-modified HuFOLactis-activated immune cells within tumor spheroids. The efficacy of iRGD modified HuFOLactis-activated immune cells against tumors was assessed in xenograft mouse models. HuFOLactis treatment resulted in notable immune cell activation, demonstrated by elevated levels of CD25, CD69, and CD137. Additionally, these activated immune cells showed heightened cytokine production and enhanced cytotoxicity against MKN45 cell lines. Incorporation of the iRGD modification facilitated the infiltration of HuFOLactis-activated immune cells into multicellular spheroids (MCSs). Additionally, immune cells activated by HuFOLactis and modified with iRGD, in combination with anti-PD-1 treatment, effectively halted tumor growth and prolonged survival in a mouse model of gastric cancer.

Targeting vascular disrupting agent-treated tumor microenvironment with tissue-penetrating nanotherapy

Cancer treatment with vascular disrupting agents (VDAs) causes rapid and extensive necrosis in solid tumors. However, these agents fall short in eliminating all malignant cells, ultimately leading to tumor regrowth. Here, we investigated whether the molecular changes in the tumor microenvironment induced by VDA treatment sensitize the tumors for secondary nanotherapy enhanced by clinical-stage tumor penetrating peptide iRGD. Treatment of peritoneal carcinomatosis (PC) and breast cancer mice with VDA combretastatin A-4 phosphate (CA4P) resulted in upregulation of the iRGD receptors αv-integrins and NRP-1, particularly in the peripheral tumor tissue. In PC mice treated with CA4P, coadministration of iRGD resulted in an approximately threefold increase in tumor accumulation and a more homogenous distribution of intraperitoneally administered nanoparticles. Notably, treatment with a combination of CA4P, iRGD, and polymersomes loaded with a novel anthracycline Utorubicin (UTO-PS) resulted in a significant decrease in the overall tumor burden in PC-bearing mice, while avoiding overt toxicities. Our results indicate that VDA-treated tumors can be targeted therapeutically using iRGD-potentiated nanotherapy and warrant further studies on the sequential targeting of VDA-induced molecular signatures.

Tumor-penetrating iRGD facilitates penetration of poly(floxuridine-ketal)-based nanomedicine for enhanced pancreatic cancer therapy

Efficient intratumoral penetration is essential for nanomedicine to eradicate pancreatic tumors. Although nanomedicine can enter the perivascular space of pancreatic tumors, their access to distal tumor cells, aloof from the vessels, remains a formidable challenge. Here, we synthesized an acid-activatable macromolecular prodrug of floxuridine (FUDR)—poly(FUDR-ketal), engineered a micellar nanomedicine of FUDR, and intravenously co-administered the nanomedicine with the tumor-penetrating peptide iRGD for enhanced treatment of pancreatic tumor. A FUDR-derived mono-isopropenyl ether was synthesized and underwent self-addition polymerization to afford the hydrophobic poly(FUDR-ketal), which was subsequently co-assembled with amphiphilic DSPE-mPEG into the micellar nanomedicine with size of 12 nm and drug content of 56.8 wt% using nanoprecipitation technique. The acetone-based ketal-linked poly(FUDR-ketal) was triggered by acid to release FUDR to inhibit cell proliferation. In an orthotopic pancreatic tumor model derived from KPC (KrasLSL-G12D/+; Trp53LSL-R172H/+; Pdx1-Cre) cells that overexpress neuropilin-1 (NRP-1) receptor, iRGD improved penetration of FUDR nanomedicine into tumor parenchyma and potentiated the therapeutic efficacy. Our nanoplatform, along with iRGD, thus appears to be promising for efficient penetration and activation of acid-responsive nanomedicines for enhanced pancreatic cancer therapy.

IRGD-modified erythrocyte membrane biomimetic temozolomide nanodots for the treatment of glioblastoma

The crossing of the blood-brain barrier (BBB) for conventional anticancer drugs is still a big challenge in treating glioma. The biomimetic nanoparticle delivery system has attracted increasing attention and has a promising future for crossing the BBB. Herein, we construct a multifunctional biomimetic nanoplatform using the erythrocyte membrane (EM) with the tumor-penetrating peptide iRGD (CRGDK/RGPD/EC) as a delivery, and the inner core loaded with the chemotherapeutic drug temozolomide (TMZ). The resulting biomimetic nanoparticle has perfect biocompatibility and stealth ability, which will provide more chances to escape the reticuloendothelial system (RES) entrapment, and increase the opportunity to enter the tumor site. Moreover, the decorated iRGD has been extensively used to actively targeting and deliver therapeutic agents across the BBB into glioma tissue. We show that this biomimetic delivery of TMZ with a diameter of 22 nm efficiently slowed the growth of glioblastoma multiforme (GBM) and increased the survival rate of the 30 d from 0% to 100%.

Abstract 2470: Harnessing cytomegalovirus immunity against pancreatic tumors for immunotherapy

Abstract Immunotherapy has had very limited success in pancreatic cancer, due to its low mutational burden and immunosuppressive microenvironment. Our approach consists in redirecting pre-existing antiviral immunity against pancreatic tumors by delivering viral antigens using the tumor penetrating peptide iRGD .This peptide, targets the tumor vasculature through αv integrins and neuropilin-1, delivering conjugated or co-administered cargo to tumors. Here we used mouse cytomegalovirus (CMV) as an infection model. CMV is a β-herpesvirus that induces a strong T-cell response in mice and humans, comprising >10% of all circulating CD4 and CD8 T cells mostly with effector-memory phenotype. Importantly, human CMV infects over 60% of the world’s population rendering it a suitable candidate for translation. Mice latently infected with CMV were orthotopically implanted with KPC pancreatic tumor cells and treated with systemic injections of vehicle or iRGD plus CMV class I and II binding peptides. Another cohort of age matched uninfected mice was used as a control. Tumor growth and mouse weight were monitored twice a week and CMV specific immune responses were measured in spleen and tumor by flow cytometry, using tetramer staining and CMV specific peptide recall. CMV infected mice receiving iRGD + CMV peptides responded to treatment as evidenced by delayed tumor growth associated with increased tumor necrosis and T cell infiltration. In addition, flow cytometry analysis of tumor and spleen showed a significant increase in CMV specific T cells that produced significant amounts of IFN-γ and TNF-α upon CMV peptide recall. Furthermore, tumor regulatory T cells (Treg) were significantly reduced and the CD8/T reg ratio was greatly increased. Survival studies showed a 68% increase in median survival in the treated and infected group. Combining this strategy with anti-PD1 and or anti-IL10R did not significantly improve the benefits of iRGD + CMV therapy alone. Other combinations with chemotherapy and TME remodeling agents are being tested.Taken together, this data shows we can deliver antigens to pancreatic tumors via iRGD and elicit an anti-tumor immune response that results in delayed tumor growth and has a survival benefit. This is a mutation agnostic approach with high translational value, since more than 60% of the population has previous CMV immunity and iRGD in combination with chemotherapy is already in phase II clinical trials for advanced pancreatic cancer. Citation Format: Remi Marrocco, Jay Patel, Siming Sun, Rithika Medari, Kevin Gulay, Eduardo Lucero-Meza, Evangeline Mose, Andrew Lowy, Chris Benedict, Tatiana Hurtado de Mendoza. Harnessing cytomegalovirus immunity against pancreatic tumors 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 2470.

Enhanced Tumor Targeting and Penetration of Proteolysis-Targeting Chimeras through iRGD Peptide Conjugation: A Strategy for Precise Protein Degradation in Breast Cancer.

Proteolysis-targeting chimeras (PROTACs) have recently emerged as a promising technology for drug development. However, poor water solubility, limited tissue selectivity, and inadequate tumor penetration pose significant challenges for PROTAC-based therapies in cancer treatment. Herein, we developed an iRGD-PROTAC conjugation strategy utilizing tumor-penetrating cyclic peptide iRGD (CRGDK/RGPD/EC) to deliver PROTACs deep into breast cancer tissues. As a conceptual validation study, iRGD peptides were conjugated with a bromodomain-containing protein 4 (BRD4) PROTAC through a GSH-responsive linker. The resulting iRGD-PROTAC conjugate iPR showed enhanced water solubility, tumor-targeting capability, and penetration within tumor tissues, resulting in increased antibreast cancer efficacy in animal models and patient-derived organoids. This study demonstrates the advantages of combining iRGD and PROTACs in improving drug delivery and highlights the importance of tissue selectivity and penetration ability in PROTAC-based therapeutics.

Exploration of tumor penetrating peptide iRGD as a potential strategy to enhance tumor penetration of cancer nanotherapeutics.

Cancer therapy continues to be a huge challenge as most chemotherapeutic agents exert serious adverse effects on healthy organs. Chemotherapeutic agents lack selective targeting and even the existing target specific therapies are failing due to poor distribution into the tumor microenvironment. Nanotechnology offers multiple advantages to address the limitations encountered by conventional therapy. However, the delivery of nanotherapeutics to tumor tissue has not improved over the years partly due to the poor and inadequate distribution of nanotherapeutics into deeper tumor regions resulting in resistance and relapse. To curb the penetration concerns, iRGD was explored and found to be highly effective in improving the delivery of cancer nanomedicine. The preclinical observations are highly encouraging; however, the clinical translation is at a nascent stage. Based on this, we have made an elaborative effort to give a detailed account of various promising applications of iRGD to increase anticancer and tumor imaging potential. Importantly, we have comprehensively discussed the shortcomings and uncertainties associated with the clinical translation of iRGD-based therapeutic approaches and future directions.

IRGD-modified memory-like NK cells exhibit potent responses to hepatocellular carcinoma

BackgroundCytokine-induced memory-like natural killer (CIML NK) cells have been found to possess potent antitumor responses and induce complete remissions in patients with leukemia. However, the poor infiltration of transferred NK cells is a major obstacle in developing adoptive cell immunotherapy for solid tumors. In our study, we explored the potential of using the tumor-penetrating peptide iRGD to deliver activated CIML NK cells deep into tumor tissues.MethodsAfter being briefly stimulated with interleukin-12 (IL-12), IL-15, and IL-18, CIML NK cells were assessed for their phenotype and function with flow cytometry. The penetrating and killing capability of iRGD-modified CIML NK cells in tumor spheroids was revealed by confocal microscopy. The anti-tumor efficacy of these modified CIML NK cells was tested in hepatocellular carcinoma (HCC) xenograft mouse models.ResultsTreating NK cells with cytokines led to a substantial activation, which was evidenced by the upregulation of CD25 and CD137. After a resting period of six days, CIML NK cells were still able to display strong activation when targeting HepG2 and SK-Hep-1 HCC cell lines. Additionally, CIML NK cells produced increased amounts of cytokines (interferon-gamma and tumor necrosis factor alpha) and exhibited heightened cytotoxicity towards HCC cell lines. The iRGD modification enabled CIML NK cells to infiltrate multicellular spheroids (MCSs) and, consequently, to induce cytotoxicity against the target cancer cells. Moreover, the CIML NK cells modified with iRGD significantly decreased tumor growth in a HCC xenograft mouse model.ConclusionOur findings demonstrate that CIML NK cells possess augmented potency and durability against HCC cell lines in vitro. Additionally, we have seen that the incorporation of iRGD to CIML NK cells facilitates enhanced infiltration and targeted destruction of MCSs. Moreover, the application of iRGD-modified CIML NK cells reveal remarkable anti-tumor efficacy against HCC in vivo.

131TiP ASCEND: Randomized, double-blinded phase II study of gemcitabine and nab-paclitaxel with CEND-1 or placebo in untreated metastatic pancreatic ductal adenocarcinoma - An Australasian Gastro-Intestinal Trials Group (AGITG) trial ACTRN12621001290886

Most patients with pancreatic ductal adenocarcinoma (PDAC) present with unresectable or metastatic disease. Standard first line chemotherapy is with gemcitabine and nab-paclitaxel, or FOLFIRINOX and median overall survival (OS) remains poor, under 12 months. The dense PDAC stroma acts as a barrier to drug delivery. CEND-1 is a novel cyclic tumor-penetrating peptide iRGD (internalizing arginylglycylaspartic acid) that may improve drug delivery by activating an endocytic/exocytic transport pathway by binding αvB3/5-integrins and downstream neuropilin-1.

Enhanced antitumor effect of icariin nanoparticles coated with iRGD functionalized erythrocyte membrane

Lung cancer is the most common cause of incidence and mortality among tumor diseases. Icariin (ICA), a potential Chinese medicine monomer, has been reported to show outstanding antitumor effects. However, the hydrophobic nature and less tumor penetration limit its potential as a topical healing agent. There are few studies report the efficacy of ICA on lung cancer, moreover, there is no biomimetic targeted delivery system in the application of ICA. Herein, we firstly develop a novel ICA bionic targeted nano-preparation, camouflaged by the tumor penetrating peptide iRGD (cRGDKGPDC), functionalized red blood cell membrane (RBCM), has the increased solubility, utilized biocompatibility, and aggravated tumor penetration of ICA. In this study, we constructed the iRGD functionalized RBCM mimetic targeted ICA-loaded nanoparticles (iRINPs) and explored the anti-tumor effect of iRINPs against lung cancer with biochemical and behavioral analysis. The results suggested that iRINPs showed improved biocompatibility and stability, and reduced phagocytic uptakes by macrophages. Besides, the modification of iRGD significantly improved the targeting ability of iRINPs. In vitro and in vivo the treatment effects and safety assays showed that iRINPs attained better therapeutic effects than ICA by inhibiting A549 cell migration, proliferation and invasion, as well as reducing side effects of ICA. Overall, we expected that the new bionic nanocarriers would be a promising nano-platform for ICA in the precise therapy of lung cancer.

Ferroptosis-induced anticancer effect of resveratrol with a biomimetic nano-delivery system in colorectal cancer treatment

Ferroptosis is a novel form of programmed cell death impelled by iron-dependent lipid peroxidation, which may be a potential strategy for cancer therapy. Here we demonstrated for the first time that Resveratrol (RSV), a traditional Chinese medicine (TCM) chemical monomer, could effectually inhibit the growth of colon cancer cells through the ROS-dependent ferroptosis pathway. Mechanistically, RSV evoked the increase of reactive oxygen species and lipid peroxidation in colorectal cancer cells, and eventually lead to ferroptosis. Furthermore, RSV could promote ferroptosis by downregulating the expression of the channel protein solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4). To improve the delivery efficiency of RSV, a biomimetic nanocarrier was developed by coating RSV-loaded poly(ε-caprolactone)–poly(ethylene glycol) (PCL-PEG) nanoparticles with erythrocyte membrane (RSV-NPs@RBCm). The RSV-NPs@RBCm provide the possibility to escape macrophage phagocytosis and have a long circulation effect. In addition, when coupled with a tumor-penetrating peptide iRGD, which could trigger enhanced tissue penetration tumor-specifically, the delivery of RSV-NPs@RBCm into tumors would be significantly improved results from the in vivo study demonstrated an excellent treatment efficacy for CRC. Altogether, our study highlighted the therapeutic potential of RSV as a ferroptosis-inducing anticancer agent and when loaded into a biomimetic nanoplatform, it might pave the way for the application of RSV loaded nanosystems for colorectal cancer treatment.

Coadministration of iRGD peptide with ROS-sensitive nanoparticles co-delivering siFGL1 and siPD-L1 enhanced tumor immunotherapy

The continuous activation and expansion of tumor-specific T cells by various means are the main goal of cancer immunotherapy. Tumor cells overexpress fibrinogen-like protein 1 (FGL1) and programmmed death-ligand 1 (PD-L1), which respectively bind to lymphocyte-activation gene 3 (LAG-3) and programmmed death-1(PD-1) on T cells, forming important signaling pathways (FGL1/LAG-3 and PD-1/PD-L1) that negatively regulate immune responses. In order to interfere with the inhibitory function of FGL1 and PD-L1 proteins, we designed a new type of reactive oxygen species (ROS)-sensitive nanoparticles to load FGL1 siRNA (siFGL1) and PD-L1 siRNA (siPD-L1), which was formed from a stimuli-responsive polymer with a poly-l-lysine–thioketal and modified cis-aconitate to facilitate endosomal escape. Moreover, tumor-penetrating peptide iRGD and ROS-responsive nanoparticles were co-administered to further enhance the delivery efficiency of siFGL1 and siPD-L1, thereby significantly reducing the protein levels of FGL1 and PD-L1 in tumor cells. Our findings indicated that the dual delivery of FGL1/PD-L1 siRNA was a new and powerful treatment method, which was characterized by increasing the infiltration of effector CD4+ and CD8+ T cells, effectively alleviating the tumor immunosuppressive microenvironment. These findings also supported the superiority and feasibility of nanoparticle-mediated tumor immunotherapy, and may provide a different perspective for cancer treatment. Statement of significanceIn addition to the idea that cancer vaccines can promote T cell immune responses, nanoparticle delivery modulators (such as small interfering RNA (siRNA) targeting immunosuppressive pathways) may provide more information for the research of nanoparticle-mediated cancer immunotherapy. In this study, we designed a new intelligent nano-delivery system for co-delivery of siFGL1 and siPD-L1, and demonstrated the ability to down-regulate the expression levels of FGL1 and PD-L1 proteins in tumor cells in vitro and in vivo. The constructed nanoparticle had a good tumor microenvironment responsiveness, and the delivery efficiency was enhanced by co-injection with tumor penetrating peptide iRGD. This project proposed a new strategy for tumor immunotherapy based on smart nano-delivery systems, and explored more possibilities for tumor therapy.

Bifunctional iRGD-anti-CD3 enhances antitumor potency of T cells by facilitating tumor infiltration and T-cell activation

BackgroundPoor infiltration and limited activation of transferred T cells are fundamental factors impeding the development of adoptive cell immunotherapy in solid tumors. A tumor-penetrating peptide iRGD has been widely used...

Tumor-penetrating therapy for \u03b25 integrin-rich pancreas cancer

Pancreatic ductal adenocarcinoma (PDAC) is characterized by marked desmoplasia and drug resistance due, in part, to poor drug delivery to extravascular tumor tissue. Here, we report that carcinoma-associated fibroblasts (CAFs) induce β5 integrin expression in tumor cells in a TGF-β dependent manner, making them an efficient drug delivery target for the tumor-penetrating peptide iRGD. The capacity of iRGD to deliver conjugated and co-injected payloads is markedly suppressed when β5 integrins are knocked out in the tumor cells. Of note, β5 integrin knock-out in tumor cells leads to reduced disease burden and prolonged survival of the mice, demonstrating its contribution to PDAC progression. iRGD significantly potentiates co-injected chemotherapy in KPC mice with high β5 integrin expression and may be a powerful strategy to target an aggressive PDAC subpopulation.

Macrophage-Membrane-Camouflaged Disintegrable and Excretable Nanoconstruct for Deep Tumor Penetration.

The consolidation of nanovectors with biological membranes has recently been a subject of interest owing to the prolonged systemic circulation time and delayed clearance by the reticuloendothelial system of such systems. Among the different biomembranes, the macrophage membrane has a similar systemic circulation time, with an additional chemotactic aptitude, targeting integrin proteins. In this study, we aimed to establish a laser-activated, disintegrable, and deeply tumor-penetrative nanoplatform. We used a highly tumor-ablative and laser-responsive disintegrable copper sulfide nanoparticle, loaded it with paclitaxel, and camouflaged it with the macrophage membrane for the fabrication of PTX@CuS@MMNPs. The in vitro paclitaxel release profile was favorable for release in the tumor microenvironment, and the release was accelerated after laser exposure. Cellular internalization was improved by membrane encapsulation. Cellular uptake, cytotoxicity, reactive oxygen species generation, and apoptosis induction of PTX@CuS@MMNPs were further improved upon laser exposure, and boosted permeation was achieved by co-administration of the tumor-penetrating peptide iRGD. In vivo tumor accumulation, tumor inhibition rate, and apoptotic marker expression induced by PTX@CuS@MMNPs were significantly improved by laser irradiation and iRGD co-administration. PTX@CuS@MMNPs induced downregulation of cellular proliferation and angiogenic markers but no significant changes in body weight, survival, or significant toxicities in vital organs after laser exposure, suggesting their biocompatibility. The disintegrability of the nanosystem, accredited to biodegradability, favored efficient elimination from the body. In conclusion, PTX@CuS@MMNPs showed promising traits in combination therapies for excellent tumor eradication.

<p>Antitumor Activity of Thermosensitive Hydrogels Packaging Gambogic Acid Nanoparticles and Tumor-Penetrating Peptide iRGD Against Gastric Cancer</p>

IntroductionGambogic acid (GA) is proved to have anti-tumor effects on gastric cancer. Due to poor solubility, non-specific biological distribution, toxicity to normal tissues and short half-life, it is hard to be applied into the clinic. To overcome these issues, we developed a thermosensitive and injectable hydrogel composed of hydroxypropyl cellulose, silk fibroin and glycerol, with short gelling time, good compatibility and sustained release, and demonstrated that the hydrogel packaged with gambogic acid nanoparticles (GA-NPs) and tumor-penetrating peptide iRGD could improve the anti-tumor activity.MethodsThe Gelling time and micropore size of the hydrogels were regulated through different concentrations of glycerol. Controlled release characteristics of the hydrogels were evaluated with a real-time near-infrared fluorescence imaging system. Location of nanoparticles from different carriers was traced by confocal laser scanning microscopy. The in vivo antitumor activity of the hydrogels packaging GA-NPs and iRGD was evaluated by investigating tumor volume and tumor size.ResultsThe thermo-sensitive properties of hydrogels were characterized by 3–4 min, 37°C, when glycerol concentration was 20%. The hydrogels physically packaged with GA-NPs and iRGD showed higher fluorescence intensity than other groups. The in vivo study indicated that the co-administration of GA-NPs and iRGD by hydrogels had higher antitumor activity than the GA-loaded hydrogels and free GA combining with iRGD. Free GA group showed few antitumor effects. Compared with the control group, the body weight in other groups had no obvious change, and the count of leukocytes and hemoglobin was slightly decreased.DiscussionThe hydrogel constructed iRGD and GA-NPs exerted an effective anti-tumor effect possibly due to retention effect, local administration and continuous sustained release of iRGD promoting the penetration of nanoparticles into a deep part of tumors. The delivery system showed little systemic toxicity and would provide a promising strategy to improve anti-gastric cancer efficacy.

Co-Administration Of iRGD Enhances Tumor-Targeted Delivery And Anti-Tumor Effects Of Paclitaxel-Loaded PLGA Nanoparticles For Colorectal Cancer Treatment.

BackgroundNanoparticles exhibit great promise for improving the solubility and tissue-specific distribution of chemotherapeutic agents; however, the passive and highly variable enhanced permeability and retention (EPR) effects observed in tumors frequently leads to insufficient delivery of nanodrugs into tumors. The tumor-penetrating peptide iRGD can actively enhance tumor-selective delivery of nanoparticles into tumors by binding to integrin and interacting with tissue-penetrating receptor neuropilin-1.Materials and methodsTo improve colorectal cancer treatment, in this study, we prepared a paclitaxel (PTX)-loaded PLGA nanoparticle (PLGA-PTX) and evaluated its tumor-targeting and antitumor activity by co-administration with iRGD.ResultsCompared to free PTX, encapsulated PTX retained preferential cytotoxicity toward various colorectal cancer cells while effectively sparing healthy cells. PLGA-PTX treatment resulted in cell cycle arrest at the G2/M phase and apoptosis, leading to inhibition of cancer cell migration and invasion. PLGA-PTX combined with iRGD displayed little enhancement of cytotoxicity in vitro. Despite this, iRGD receptors integrin and neuropilin-1 were found to be primarily overexpressed on abundant tumor vessels in mice bearing colorectal tumors. Consequently, co-administration of nanoparticles with iRGD promoted the selective delivery of nanoparticles into tumor tissues in vivo. Additionally, the combined regimen enhanced the antitumor effects compared to those of each individual reagent.ConclusionOur findings suggest that PLGA nanoparticles combined with the iRGD peptide provide a promising drug delivery strategy for facilitating active drug accumulation into tumors, given that iRGD receptors are overexpressed on tumor vessels. This co-administration system lacking covalent conjugation provides a more convenient means to combine various therapeutic agents with iRGD to achieve personalized nanotherapy.

Modification of IL-24 by tumor penetrating peptide iRGD enhanced its antitumor efficacy against non-small cell lung cancer

Interleukin-24 (IL-24) is known for its tumor suppressive activity and the selective induction of apoptosis of numerous human cancer cells, while demonstrating little harm to normal cells. However, poor tumor penetration remains a key problem for the efficacy of IL-24 as a treatment. The iRGD (CRGDK/RGPDC) is a novel tumor-specific peptide with unique tumor-penetrating and cell-internalizing properties. To enhance the tumor-penetrating effects of IL-24, the iRGD peptide was fused with the C-terminal domain of IL-24 to generate a novel recombinant protein, IL-24-iRGD. The aim of the present study was to investigate the antitumor effects of IL-24-iRGD in non-small cell lung cancer (NSCLC) cells in vitro and in vivo. It was observed that IL-24-iRGD increased the production of IL-6, TNF-α and INF-γ from human peripheral blood monocyte (PBMC), and suppressed cell growth of A549 in vitro. Then A549 cells were subcutaneously injected into nude mice, and these tumor-bearing mice were immunized with IL-24, IL-24-iRGD or PBS via the tail vein. The IL-24 and IL-24-iRGD-treated groups exhibited tumor growth inhibition rates of 26.2% and 59.1%, respectively, when compared with the PBS-treated group. Protein penetration into tumors was analyzed by immunofluorescence, cell apoptosis was examined by TdT-mediated dUTP nick end labeling, and the expression of cleaved caspase-3 was analyzed by immuno-histochemical staining. The results demonstrated that IL-24-iRGD induced apoptosis and inhibited the growth of A549 cells to a significantly greater extent when compared with IL-24 treatment alone. It may provide an improved strategy for antitumor therapy and the clinical treatment of NSCLC.

Improved Anticancer Effect of Recombinant Protein izTRAIL Combined with Sorafenib and Peptide iRGD.

One of the main problems in oncology is the development of drugs that cause the death of cancer cells without damaging normal cells. Another key problem to be solved is to suppress the drug resistance of cancer cells. The third important issue is to provide effective penetration of drug molecules to cancer cells. TRAIL (TNFα-related apoptosis inducing ligand)/Apo2L is a highly selective anticancer agent. However, the recombinant TRAIL protein having high efficiency against cancer cells in vitro was not effective in clinical trials. Recently we have discovered an acquisition of TRAIL resistance by cancer cells in confluent cultures, which is apparently a manifestation of the general phenomenon of multicellular resistance. The aim of this study was to evaluate whether the anticancer effect of the recombinant protein TRAIL in vivo can be improved by the suppression of multicellular TRAIL-resistance using sorafenib and a tumor-penetrating peptide iRGD, c(CRGDKGPDC). The results testified a great increase in the resistance of human fibrosarcoma HT-1080 cells to izTRAIL both in confluent cultures and in spheroids. Sorafenib administered at nontoxic concentration effectively suppressed confluent- or spheroid-mediated TRAIL-resistance of HT-1080 cells in vitro. Sorafenib combined with iRGD significantly improved the anticancer effect of the recombinant protein izTRAIL in HT-1080 human fibrosarcoma grafts in BALB/c nude mice. Consistent with this finding, multicellular TRAIL-resistance may be a reason of inefficacy of izTRAIL alone in vivo. The anticancer effect of the recombinant protein izTRAIL in vivo may be improved in combination with sorafenib, an inhibitor of multicellular TRAIL resistance and iRGD, the tumor-penetrating peptide.