Pablo Scodeller

iRGD peptide conjugation potentiates intraperitoneal tumor delivery of paclitaxel with polymersomes.

Polymersomes are versatile nanoscale vesicles that can be used for cytoplasmic delivery of payloads. Recently, we demonstrated that pH-sensitive polymersomes exhibit an intrinsic selectivity towards intraperitoneal tumor lesions. A tumor homing peptide, iRGD, harbors a cryptic C-end Rule (CendR) motif that is responsible for neuropilin-1 (NRP-1) binding and for triggering extravasation and tumor penetration of the peptide. iRGD functionalization increases tumor selectivity and therapeutic efficacy of systemic drug-loaded nanoparticles in many tumor models. Here we studied whether intraperitoneally administered paclitaxel-loaded iRGD-polymersomes show improved efficacy in the treatment of peritoneal carcinomatosis. First, we demonstrated that the pH-sensitive polymersomes functionalized with RPARPAR (a prototypic CendR peptide) or iRGD internalize in the cells that express NRP-1, and that internalized polymersomes release their cargo inside the cytosol. CendR-targeted polymersomes loaded with paclitaxel were more cytotoxic on NRP-1-positive cells than on NRP-1-negative cells. In mice bearing peritoneal tumors of gastric (MKN-45P) or colon (CT26) origin, intraperitoneally administered RPARPAR and iRGD-polymersomes showed higher tumor-selective accumulation and penetration than untargeted polymersomes. Finally, iRGD-polymersomes loaded with paclitaxel showed improved efficacy in peritoneal tumor growth inhibition and in suppression of local dissemination compared to the pristine paclitaxel-polymersomes or Abraxane. Our study demonstrates that iRGD-functionalization improves efficacy of paclitaxel-polymersomes for intraperitoneal treatment of peritoneal carcinomatosis.

A tumor-penetrating peptide enhances circulation-independent targeting of peritoneal carcinomatosis

Peritoneal carcinomatosis is a major source of morbidity and mortality in patients with advanced abdominal neoplasms. Intraperitoneal chemotherapy (IPC) is an area of intense interest given its efficacy in ovarian cancer. However, IPC suffers from poor drug penetration into peritoneal tumors. As such, extensive cytoreductive surgery is required prior to IPC. Here, we explore the utility of iRGD, a tumor-penetrating peptide, for improved tumor-specific penetration of intraperitoneal compounds and enhanced IPC in mice. Intraperitoneally administered iRGD significantly enhanced penetration of an attached fluorescein into disseminated peritoneal tumor nodules. The penetration was tumor-specific, circulation-independent, and mediated by the neuropilin-binding RXXK tissue-penetration peptide motif of iRGD. Q-iRGD, which fluoresces upon cleavage, including the one that leads to RXXK activation, specifically labeled peritoneal metastases displaying different growth patterns in mice. Importantly, iRGD enhanced intratumoral entry of intraperitoneally co-injected dextran to approximately 300% and doxorubicin to 250%. Intraperitoneal iRGD/doxorubicin combination therapy inhibited the growth of bulky peritoneal tumors and reduced systemic drug toxicity. iRGD delivered attached fluorescein and co-applied nanoparticles deep into fresh human peritoneal metastasis explants. These results indicate that intraperitoneal iRGD co-administration serves as a simple and effective strategy to facilitate tumor detection and improve the therapeutic index of IPC for peritoneal carcinomatosis.

Paclitaxel-Loaded Polymersomes for Enhanced Intraperitoneal Chemotherapy

Peritoneal carcinomatosis is present in more than 60% of gastric cancer, 40% of ovarian cancer, and 35% of colon cancer patients. It is the second most common cause of cancer-related mortality, with a median survival of 1 to 3 months. Cytoreductive surgery combined with intraperitoneal chemotherapy is the current clinical treatment, but achieving curative drug accumulation and penetration in peritoneal carcinomatosis lesions remains an unresolved challenge. Here, we used flexible and pH-sensitive polymersomes for payload delivery to peritoneal gastric (MKN-45P) and colon (CT26) carcinoma in mice. Polymersomes were loaded with paclitaxel and in vitro drug release was studied as a function of pH and time. Paclitaxel-loaded polymersomes remained stable in aqueous solution at neutral pH for up to 4 months. In cell viability assay on cultured cancer cell lines (MKN-45P, SKOV3, CT26), paclitaxel-loaded polymersomes were more toxic than free drug or albumin-bound paclitaxel (Abraxane). Intraperitoneally administered fluorescent polymersomes accumulated in malignant lesions, and immunofluorescence revealed an intense signal inside tumors with no detectable signal in control organs. A dual targeting of tumors was observed: direct (circulation-independent) penetration, and systemic, blood vessel–associated accumulation. Finally, we evaluated preclinical antitumor efficacy of paclitaxel-polymersomes in the treatment of MKN-45P disseminated gastric carcinoma using a total dose of 7 mg/kg. Experimental therapy with paclitaxel-polymersomes improved the therapeutic index of drug over free paclitaxel and Abraxane, as evaluated by intraperitoneal tumor burden and number of metastatic nodules. Our findings underline the potential utility of the polymersome platform for delivery of drugs and imaging agents to peritoneal carcinomatosis lesions. Mol Cancer Ther; 15(4); 670–9. ©2016 AACR.

Hyaluronan-binding peptide for targeting peritoneal carcinomatosis:

Peritoneal carcinomatosis results from dissemination of solid tumors in the peritoneal cavity, and is a common site of metastasis in patients with carcinomas of gastrointestinal or gynecological origin. Peritoneal carcinomatosis treatment is challenging as poorly vascularized, disseminated peritoneal micro-tumors are shielded from systemic anticancer drugs and drive tumor regrowth. Here, we describe the identification and validation of a tumor homing peptide CKRDLSRRC (IP3), which upon intraperitoneal administration delivers payloads to peritoneal metastases. IP3 peptide was identified by in vivo phage display on a mouse model of peritoneal carcinomatosis of gastric origin (MKN-45P), using high-throughput sequencing of the peptide-encoding region of phage genome as a readout. The IP3 peptide contains a hyaluronan-binding motif, and fluorescein-labeled IP3 peptide bound to immobilized hyaluronan in vitro. After intraperitoneal administration in mice bearing peritoneal metastases of gastric and colon origin, IP3 peptide homed robustly to macrophage-rich regions in peritoneal tumors, including poorly vascularized micro-tumors. Finally, we show that IP3 functionalization conferred silver nanoparticles the ability to home to peritoneal tumors of gastric and colonic origin, suggesting that it could facilitate targeted delivery of nanoscale payloads to peritoneal tumors. Collectively, our study suggests that the IP3 peptide has potential applications for targeting drugs, nanoparticles, and imaging agents to peritoneal tumors.

Identification of a peptide recognizing cerebrovascular changes in mouse models of Alzheimer’s disease

Cerebrovascular changes occur in Alzheimer’s disease (AD). Using in vivo phage display, we searched for molecular markers of the neurovascular unit, including endothelial cells and astrocytes, in mouse models of AD. We identified a cyclic peptide, CDAGRKQKC (DAG), that accumulates in the hippocampus of hAPP-J20 mice at different ages. Intravenously injected DAG peptide homes to neurovascular unit endothelial cells and to reactive astrocytes in mouse models of AD. We identified connective tissue growth factor (CTGF), a matricellular protein that is highly expressed in the brain of individuals with AD and in mouse models, as the target of the DAG peptide. We also showed that exogenously delivered DAG homes to the brain in mouse models of glioblastoma, traumatic brain injury, and Parkinson’s disease. DAG may potentially be used as a tool to enhance delivery of therapeutics and imaging agents to sites of vascular changes and astrogliosis in diseases associated with neuroinflammation.Cerebrovascular changes and astrogliosis occur in Alzheimer’s disease (AD). Using an in vivo phage display technique, the authors identified a peptide that upon systematic administration, can home to brain endothelial cells and astrocytes in mouse models of AD at the early stages of the disease.

Extracellular Matrix Degrading Enzymes for Nanocarrier-Based Anticancer Therapy

Perfusion is seriously hampered in solid tumors that overexpress extracellular matrix components like hyaluronic acid, collagen and chondroitin sulfate. Tumor penetration of circulating material is most affected for nanocarriers because of their size and lower diffusion. Due to this, the aid of enzymes that degrade the matrix becomes essential when applying nanocarrier based anticancer therapies like oncolytic viruses or nano-formulated drugs like Abraxane or Doxil.

Detection of small breast tumors using tumor penetrating-polymersomes engineered to target p32 protein

Triple negative breast cancer (TNBC) is the deadliest form of breast cancer and its successful treatment critically depends on early diagnosis and therapy. The multi-compartment protein p32 is overexpressed and present at cell surfaces in a variety of tumors, including TNBC, specifically in the malignant cells and endothelial cells, and in macrophages localized in hypoxic areas of the tumor. Herein we used polyethylene glycol-polycaprolactone polymersomes that were affinity targeted with the p32-binding tumor penetrating peptide LinTT1 (AKRGARSTA) for imaging of TNBC lesions. A tyrosine residue was added to the peptide to allow for 124I labeling and PET imaging. In a TNBC model in mice, systemic LinTT1-targeted polymersomes accumulated in early tumor lesions more than twice as efficiently as untargeted polymersomes with up to 20% ID/cc at 24 h after administration. The PET-imaging was very sensitive, allowing detection of tumors as small as ~20mm3. Confocal imaging of tumor tissue sections revealed a high degree of vascular exit and stromal penetration of LinTT1-targeted polymersomes and co-localization with tumor-associated macrophages. Our studies show that systemic LinTT1-targeted polymersomes can be potentially used for precision-guided tumor imaging and treatment of TNBC.Triple negative breast cancer (TNBC) is the deadliest form of breast cancer and its successful treatment critically depends on early diagnosis and therapy. The multi-compartment protein p32 is overexpressed and present at cell surfaces in TNBC, specifically in the malignant cells and endothelial cells, and in macrophages localized in hypoxic areas of the tumor. Herein we used polyethylene glycol-polycaprolactone polymersomes that were affinity targeted with the p32-binding tumor penetrating peptide LinTT1 (AKRGARSTA) for imaging of TNBC lesions. A tyrosine residue was added to the peptide to allow for 124I labeling and PET imaging. Systemic LinTT1-targeted polymersomes accumulated in early tumor lesions more than twice as efficiently as untargeted polymersomes with up to 20% ID/cc at 24 h after administration. The PET-imaging was very sensitive, allowing detection of tumors as small as ~20mm3. Confocal imaging of tumor tissue sections revealed a high degree of vascular exit and stromal penetration of LinTT1-targeted polymersomes and co-localization with tumor-associated macrophages. Our studies show that systemic LinTT1-targeted polymersomes can be potentially used for precision-guided tumor imaging and treatment of TNBC. uFigure1 Small triple negative brast tumors can be detected with LinTT1-conjugated polymersomes. Radiolabeled LinTT1-polymersomes were intravenously injected into mice bearing small triple negative breast tumor. LinTT1 peptide binds to p32 protein expressed in the surface of tumor cells and activated macrophage/myeloid cells. LinTT1 is cleaved by urokinase type plasminogen activator (uPA) in tumor, and the processed peptide binds to NRP-1, triggering the penetration of polymersomes into the tumor tissue.

Application of polymersomes engineered to target p32 protein for detection of small breast tumors in mice

Triple negative breast cancer (TNBC) is the deadliest form of breast cancer and its successful treatment critically depends on early diagnosis and therapy. The multi-compartment protein p32 is overexpressed and present at cell surfaces in a variety of tumors, including TNBC, specifically in the malignant cells and endothelial cells, and in macrophages localized in hypoxic areas of the tumor. Herein we used polyethylene glycol-polycaprolactone polymersomes that were affinity targeted with the p32-binding tumor penetrating peptide LinTT1 (AKRGARSTA) for imaging of TNBC lesions. A tyrosine residue was added to the peptide to allow for 124I labeling and PET imaging. In a TNBC model in mice, systemic LinTT1-targeted polymersomes accumulated in early tumor lesions more than twice as efficiently as untargeted polymersomes with up to 20% ID/cc at 24 h after administration. The PET-imaging was very sensitive, allowing detection of tumors as small as ∼20 mm3. Confocal imaging of tumor tissue sections revealed a high degree of vascular exit and stromal penetration of LinTT1-targeted polymersomes and co-localization with tumor-associated macrophages. Our studies show that systemic LinTT1-targeted polymersomes can be potentially used for precision-guided tumor imaging and treatment of TNBC.

Publisher Correction: Identification of a peptide recognizing cerebrovascular changes in mouse models of Alzheimer’s disease

The original version of the Supplementary Information associated with this Article inadvertently omitted Supplementary Table 1. The HTML has now been updated to include a corrected version of the Supplementary Information.

Abstract 965: Two in one: nanotechnology based strategies for the treatment of ER+ breast cancer

Understanding endocrine resistance mechanisms is key to develop new therapeutic strategies. We focus on the role the tumor microenvironment plays as a modulator of endocrine therapy resistance in breast cancer, in particular associated to Tamoxifen. Studies show that the use of nanoparticles (NPs) as antitumor drug delivery systems is a good strategy to improve the efficacy and decrease secondary effects of conventional chemotherapies. In this context we hypothesize that a therapeutic strategy based on the use of Tamoxifen carried in NPs coated with the tumor penetrating peptide iRGD, would be more effective than conventional Tamoxifen. Neuropilin-1, that mediates iRGD induced endocytosis, has been shown to be associated to breast cancer stem cells. Thus, we postulate that our multifunctional NPs would be effective in reducing this cell population, contrary to what is observed with free Tamoxifen. Moreover, iRGD blocks the interaction between integrin β1 and fibronectin, a mechanism we have previously shown induces Tamoxifen resistance (Pontiggia et al. 2012). NPs were synthesized with polyethyleneglycol and polycaprolactone and coated with the iRGD peptide. This peptide was constructed with a FAM fluorophore in order to track the NPs. To evaluate the cell uptake, MCF-7 cells were incubated for 5 h with iRGD-NP or FAM-NP as a control. NP entry was higher when the NPs were coated with iRGD, both in 2D and in 3D cultures. Cell viability experiments revealed that Tamoxifen encapsulated in NPs was more effective than the free drug (p Citation Format: Maria Ines Diaz Bessone, Lorena Simon-Gracia, Pablo Scodeller, Tambet Teesalu, Marina Simian. Two in one: nanotechnology based strategies for the treatment of ER+ breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 965. doi:10.1158/1538-7445.AM2017-965