Chemokine-derived oncolytic peptide induces immunogenic cancer cell death and significantly suppresses tumor growth.

Chemokinostatin-1 (CKS1) is a 24-mer peptide originally discovered as an anti-angiogenic peptide derived from the CXCL1 chemokine. Here, we demonstrate that CKS1 acts not only as an anti-angiogenic peptide but also as an oncolytic peptide due to its structural and physical properties. CKS1 induced both necrotic and apoptotic cell death specifically in cancer cells while showing minimal toxicity in non-cancerous cells. Mechanistically, CKS1 disrupted the cell membrane of cancer cells quickly after treatment and activated the apoptotic pathway at later time points. Furthermore, immunogenic molecules were released from CKS1-treated cells, indicating that CKS1 induces immunogenic cell death. CKS1 effectively suppressed tumor growth in vivo. Collectively, these data demonstrate that CKS1 functions as an oncolytic peptide and has a therapeutic potential to treat cancer.

Chemokine-derived oncolytic peptide induces immunogenic cancer cell death and significantly suppresses tumor growth.

Chemokinostatin-1 (CKS1) is a 24-mer peptide originally discovered as an anti-angiogenic peptide derived from the CXCL1 chemokine. Here, we demonstrate that CKS1 acts not only as an anti-angiogenic peptide but also as an oncolytic peptide due to its structural and physical properties. CKS1 induced both necrotic and apoptotic cell death specifically in cancer cells while showing minimal toxicity in non-cancerous cells. Mechanistically, CKS1 disrupted the cell membrane of cancer cells quickly after treatment and activated the apoptotic pathway at later time points. Furthermore, immunogenic molecules were released from CKS1 treated cells, indicating that CKS1 induces immunogenic cell death. CKS1 effectively suppressed tumor growth in vivo. Collectively, these data demonstrate that CKS1 is a unique peptide that functions both as an anti-angiogenic peptide and as an oncolytic peptide and has a therapeutic potential to treat cancer.

Gel-forming therapeutic peptide exhibits sustained delivery and efficacy in a mouse model of triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a particularly aggressive and invasive subtype of breast cancer that represents a major cause of death of women worldwide. Here we describe the efficacy of an integrin-binding antiangiogenic peptide in a variety of delivery methods and dosing conditions. This peptide, AXT201, demonstrated consistent anti-tumor efficacy when administered intraperitoneally, subcutaneously, and intratumorally, and retained this activity even when dosing frequency was reduced to once every two weeks. Finally, in vivo imaging and biodistribution studies of AXT201 showed a long-term persistence of at least 10 days at the site of injection and a stable detectable signal in the blood over 48 h, indicating a sustained release profile. Taken together, these findings indicate AXT201 exhibits favorable pharmacokinetic properties for a 20-mer peptide.

Anti-angiogenic collagen IV-derived peptide target engagement with αvß3 and α5ß1 in ocular neovascularization models.

AXT107, a collagen-derived peptide that binds integrins αvß3 and α5ß1 with high affinity, suppresses vascular endothelial growth factor (VEGF) signaling, promotes angiopoietin 2-induced Tie2 activation, and suppresses neovascularization (NV) and vascular leakage. Immunohistochemical staining for αvß3 and α5ß1 was markedly increased in NV compared with normal retinal vessels. After intravitreous injection of AXT107, there was no staining with an anti-AXT107 antibody on normal vessels but robust staining of NV that co-localized with αvß3 and α5ß1. Likewise, after intravitreous injection, fluorescein amidite-labeled AXT107 co-localized with αvß3 and α5ß1 on NV but not normal vessels. AXT107 also co-localized with αv and α5 at cell-cell junctions of human umbilical vein endothelial cells (HUVECs). AXT107-integrin binding was demonstrated by ex vivo cross-linking/pull-down experiments. These data support the hypothesis that AXT107 therapeutic activity is mediated through binding αvß3 and α5ß1 which are markedly upregulated on endothelial cells in NV providing selective targeting of diseased vessels which has therapeutic and safety benefits.

The Tie2 signaling pathway in retinal vascular diseases: a novel therapeutic target in the eye.

BACKGROUND: Retinal vascular diseases such as neovascular age-related macular degeneration, diabetic retinopathy and/or diabetic macular edema, and retinal vein occlusion with macular edema-share several key pathophysiologic aspects including neovascularization, vascular permeability, and inflammation. The role of vascular endothelial growth factor (VEGF) in these processes, and the therapeutic benefits of VEGF inhibition, have been well characterized. Anti-VEGF therapy is highly effective for many patients but is not uniformly effective in all patients and imposes a significant treatment burden. More recently, the role of the Tie2 signaling pathway in the pathophysiology of retinal vascular diseases has been investigated, and the Tie2 pathway represents a novel therapeutic target for these conditions. AREAS COVERED: The index review describes the Tie2 pathway and its complementary role to the VEGF pathway in the angiogenesis cascade and will summarize studies of molecules in development to therapeutically modulate the Tie2 pathway in retinal vascular diseases. CONCLUSIONS: Activation of the Tie2 pathway leads to downstream signaling that promotes vascular health and stability and decreases vascular permeability and inflammation. AXT107 is a collagen IV-derived synthetic peptide with a dual mechanism of action that involves suppression of VEGF signaling and activation of the Tie2 pathway; these actions are accomplished by AXT107 binding to and disrupting different integrin, leading to blockade of the VEGF receptor and rearrangement of cellular Tie2 rendering it susceptible to Ang2 agonism. Other Tie2 agonist compounds are also in development, including faricimab and razuprotafib. Tie2 activation only modestly impacts angiogenesis on its own but significantly potentiates VEGF suppression. Co-regulation of the VEGF and Tie2 signaling pathways has the potential to improve functional and structural outcomes in eyes with retinal vascular diseases.

Regulation of the tumor immune microenvironment and vascular normalization in TNBC murine models by a novel peptide.

Triple-negative breast cancer (TNBC) is a highly metastatic and aggressive disease with limited treatment options. Recently, the combination of the immune checkpoint inhibitor (ICI) atezolizumab (anti-PD-L1) with nab-paclitaxel was approved following a clinical trial that showed response rates in at least 43% of patients. While this approval marks a major advance in the treatment of TNBC it may be possible to improve the efficacy of ICI therapies through further modulation of the suppressive tumor immune microenvironment (TIME). Several factors may limit immune response in TNBC including aberrant growth factor signaling, such as VEGFR2 and cMet signaling, inefficient vascularization, poor delivery of drugs and immune cells, and the skewing of immune cell populations toward immunosuppressive phenotypes. Here we investigate the immune-modulating properties of AXT201, a novel 20 amino-acid integrin-binding peptide in two syngeneic mouse TNBC models: 4T1-BALB/c and NT4-FVB. AXT201 treatment improved survival in the NT4 model by 20% and inhibited the growth of 4T1 tumors by 47% over 22 days post-inoculation. Subsequent immunohistochemical analyses of 4T1 tumors also showed a 53% reduction in vascular density and a 184% increase in pericyte coverage following peptide treatment. Flow cytometry analyses demonstrated evidence of a more favorable anti-tumor immune microenvironment following treatment with AXT201, including significant decreases in the populations of T regulatory cells, monocytic myeloid-derived suppressor cells, and PD-L1 expressing cells and increased expression of T cell functional markers. Together, these findings demonstrate immune-activating properties of AXT201 that could be developed in combination with other immunomodulatory agents in the treatment of TNBC.

Suppression of Ocular Vascular Inflammation through Peptide-Mediated Activation of Angiopoietin-Tie2 Signaling.

Persistent inflammation is a complication associated with many ocular diseases. Changes in ocular vessels can amplify disease responses and contribute to vision loss by influencing the delivery of leukocytes to the eye, vascular leakage, and perfusion. Here, we report the anti-inflammatory activity for AXT107, a non-RGD, 20-mer αvß3 and α5ß1 integrin-binding peptide that blocks vascular endothelial growth factor (VEGF)-signaling and activates tyrosine kinase with immunoglobulin and EGF-like domains 2 (Tie2) using the normally inhibitory ligand angiopoietin 2 (Ang2). Tumor necrosis factor α (TNFα), a central inflammation mediator, induces Ang2 release from endothelial cells to enhance its stimulation of inflammation and vascular leakage. AXT107 resolves TNFα-induced vascular inflammation in endothelial cells by converting the endogenously released Ang2 into an agonist of Tie2 signaling, thereby disrupting both the synergism between TNFα and Ang2 while also preventing inhibitor of nuclear factor-κB α (IκBα) degradation directly through Tie2 signaling. This recovery of IκBα prevents nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) nuclear localization, thereby blocking NF-κB-induced inflammatory responses, including the production of VCAM-1 and ICAM-1, leukostasis, and vascular leakage in cell and mouse models. AXT107 also decreased the levels of pro-inflammatory TNF receptor 1 (TNFR1) without affecting levels of the more protective TNFR2. These data suggest that AXT107 may provide multiple benefits in the treatment of retinal/choroidal and other vascular diseases by suppressing inflammation and promoting vascular stabilization.

Cytokines secreted by stromal cells in TNBC microenvironment as potential targets for cancer therapy.

In triple-negative breast cancer (TNBC), the lack of therapeutic markers and effective targeted therapies result in an incurable metastatic disease associated with a poor prognosis. Crosstalks within the tumor microenvironment (TME), including those between cancer and stromal cells, affect the tumor heterogeneity, growth, and metastasis. Previously, we have demonstrated that IL-6, IL-8, and CCL5 play a significant role in TNBC growth and metastasis. In this study, we performed a systematic analysis of cytokine factors secreted from four stromal components (fibroblasts, macrophages, lymphatic endothelial cells, and blood microvascular endothelial cells) induced by four TNBC cell types. Through bioinformatic analysis, we selected putative candidates of secreted factors from stromal cells, which are involved in EMT activity, cell proliferation, metabolism, and matrisome pathways. Among the candidates, LCN2, GM-CSF, CST3, IL-6, IL-8, and CHI3L1 are ranked highly. Significantly, Lipocalin-2 (LCN2) is upregulated in the crosstalk of stromal cells and four different TNBC cells. We validated the increase of LCN2 secreted from four stromal cells induced by TNBC cells. Using a specific LCN2 antibody, we observed the inhibition of TNBC cell growth and migration. Taken together, these results propose secreted factors as molecular targets to treat TNBC progression via crosstalk with stromal components.

Mechanistically detailed systems biology modeling of the HGF/Met pathway in hepatocellular carcinoma.

Hepatocyte growth factor (HGF) signaling through its receptor Met has been implicated in hepatocellular carcinoma tumorigenesis and progression. Met interaction with integrins is shown to modulate the downstream signaling to Akt and ERK (extracellular-regulated kinase). In this study, we developed a mechanistically detailed systems biology model of HGF/Met signaling pathway that incorporated specific interactions with integrins to investigate the efficacy of integrin-binding peptide, AXT050, as monotherapy and in combination with other therapeutics targeting this pathway. Here we report that the modeled dynamics of the response to AXT050 revealed that receptor trafficking is sufficient to explain the effect of Met-integrin interactions on HGF signaling. Furthermore, the model predicted patient-specific synergy and antagonism of efficacy and potency for combination of AXT050 with sorafenib, cabozantinib, and rilotumumab. Overall, the model provides a valuable framework for studying the efficacy of drugs targeting receptor tyrosine kinase interaction with integrins, and identification of synergistic drug combinations for the patients.

Anisotropic poly(lactic-co-glycolic acid) microparticles enable sustained release of a peptide for long-term inhibition of ocular neovascularization.

Leading causes of vision loss include neovascular age-related macular degeneration (NVAMD) and macular edema (ME), which both require frequent intravitreal injections for treatment. A safe, poly(lactic-co-glycolic acid) (PLGA)-based biodegradable polymeric microparticle (MP) delivery system was developed that encapsulates and protects a biomimetic peptide from degradation, allows sustained intraocular release through polymer hydrolysis, and demonstrates a prolonged anti-angiogenic effect in vivo in three different NVAMD animal models (a laser-induced choroidal neovascularization mouse model, a rhoVEGF transgenic mouse model, and a Tet/opsin/VEGF transgenic mouse model) following intravitreal administration. The role of copolymer composition and microparticle shape was explored and 85:15 lactide-to-glycolide PLGA formed into ellipsoidal microparticles was found to be effective at inhibiting neovascularization for at least 16 weeks in vivo. Treatments were found to not only inhibit the growth of neovascularization, but also to cause regression of the neovasculature, reduce vascular leakage, and prevent exudative retinal detachment. These particulate devices are promising for the sustained release of biologics in the eye and may be useful for treating retinal diseases. STATEMENT OF SIGNIFICANCE: Devastating retinal diseases cause blindness in millions of people around the world. Current protein-based treatments have insufficient efficacy for many patients and also necessitate frequent intravitreal injections. Here, we demonstrate a new treatment consisting of a peptide encapsulated in biodegradable microparticles. We explore the effects of copolymer composition and physical shape of polymeric microparticles and find that both modulate peptide release. Efficacy of the treatment was validated in three different mouse models and the lead formulation was determined to be effective long-term, for at least 16 weeks in vivo, following a single injection. Treatments inhibited and regressed neovascularization as well as reduced vascular leakage. Anisotropic polymeric microparticles are promising for the sustained release of biologics in the eye.

A collagen IV-derived peptide disrupts α5ß1 integrin and potentiates Ang2/Tie2 signaling.

The angiopoietin (Ang)/Tie2 signaling pathway is essential for maintaining vascular homeostasis, and its dysregulation is associated with several diseases. Interactions between Tie2 and α5ß1 integrin have emerged as part of this control; however, the mechanism is incompletely understood. AXT107, a collagen IV-derived peptide, has strong antipermeability activity and has enabled the elucidation of this previously undetermined mechanism. Previously, AXT107 was shown to inhibit VEGFR2 and other growth factor signaling via receptor tyrosine kinase association with specific integrins. AXT107 disrupts α5ß1 and stimulates the relocation of Tie2 and α5 to cell junctions. In the presence of Ang2 and AXT107, junctional Tie2 is activated, downstream survival signals are upregulated, F-actin is rearranged to strengthen junctions, and, as a result, endothelial junctional permeability is reduced. These data suggest that α5ß1 sequesters Tie2 in nonjunctional locations in endothelial cell membranes and that AXT107-induced disruption of α5ß1 promotes clustering of Tie2 at junctions and converts Ang2 into a strong agonist, similar to responses observed when Ang1 levels greatly exceed those of Ang2. The potentiation of Tie2 activation by Ang2 even extended to mouse models in which AXT107 induced Tie2 phosphorylation in a model of hypoxia and inhibited vascular leakage in an Ang2-overexpression transgenic model and an LPS-induced inflammation model. Because Ang2 levels are very high in ischemic diseases, such as diabetic macular edema, neovascular age-related macular degeneration, uveitis, and cancer, targeting α5ß1 with AXT107 provides a potentially more effective approach to treat these diseases.

Three-Dimensional Transport Model for Intravitreal and Suprachoroidal Drug Injection.

Purpose: Quantitative understanding of the transport of therapeutic macromolecules following intraocular injections is critical for the design of efficient strategies in treating eye diseases, such as neovascular (wet) age-related macular degeneration (AMD) and macular edema (ME). Antiangiogenic treatments, such as neutralizing antibodies against VEGF or recently characterized antiangiogenic peptides, have shown promise in slowing disease progression. Methods: We developed a comprehensive three-dimensional (3D) transport model for intraocular injections using published data on drug distribution in rabbit eyes following intravitreal and suprachoroidal (SC) injection of sodium fluorescein (SF), bevacizumab, and ranibizumab. The model then was applied to evaluate the distribution of small molecules and antiangiogenic proteins following intravitreal and SC injections in human eyes. Results: The model predicts that intravitreally administered molecules are substantially mixed within the vitreous following injection, and that the long-term behavior of the injected drug does not depend on the initial mixing. Ocular pharmacokinetics of different drugs is sensitive to different clearance mechanisms. Effective retinal drug delivery is impacted by RPE permeability. For VEGF antibody, intravitreal injection provides sustained delivery to the retina, whereas SC injection provides more efficient, but short-lived, retinal delivery for smaller-sized molecules. Long-term suppression of neovascularization through SC administration of antiangiogenic drugs necessitates frequent injection or sustained delivery, such as microparticle-based delivery of antiangiogenic peptides. Conclusions: A comprehensive 3D model for intravitreal and SC drug injection is developed to provide a framework and platform for testing drug delivery routes and sustained delivery devices for new and existing drugs.

Simultaneous blockade of IL-6 and CCL5 signaling for synergistic inhibition of triple-negative breast cancer growth and metastasis.

BACKGROUND: Metastatic triple-negative breast cancer (TNBC) is a heterogeneous and incurable disease. Numerous studies have been conducted to seek molecular targets to treat TNBC effectively, but chemotherapy is still the main choice for patients with TNBC. We have previously presented evidence of the important roles of interleukin-6 (IL-6) and chemokine (C-C motif) ligand 5 (CCL5) in TNBC tumor growth and metastasis. These experiments highlighted the importance of the crosstalk between cancer cells and stromal lymphatic endothelial cells (LECs) in tumor growth and metastasis. METHODS: We examined the viability and migration of MDA-MB-231-LN, SUM149, and SUM159 cells co-cultured with LECs when treated with maraviroc (CCR5 inhibitor) and tocilizumab (anti-IL-6 receptor antibody). To assess the anti-tumor effects of the combination of these two drugs in an athymic nude mouse model, MDA-MB-231-LN cells were implanted in the mammary fat pad and maraviroc (8 mg/kg, orally daily) and cMR16-1 (murine surrogate of the anti-IL-6R antibody, 10 mg/kg, IP, 3 days a week) were administrated for 5 weeks and effects on tumor growth and thoracic metastasis were measured. RESULTS: In this study, we used maraviroc and tocilizumab to confirm that IL-6 and CCL5 signaling are key pathways promoting TNBC cell proliferation and migration. Further, in a xenograft mouse model, we showed that tumor growth was dramatically inhibited by cMR16-1, the mouse version of the anti-IL6R antibody. The combination of maraviroc and cMR16-1 caused significant reduction of TNBC tumor growth compared to the single agents. Significantly, the combination of maraviroc and cMR16-1 abrogated thoracic metastasis. CONCLUSION: Taken together, these findings show that IL-6 and CCL5 signaling, which promote crosstalk between TNBC and lymphatic vessels, are key enhancers of TNBC tumor growth and metastasis. Furthermore, these results demonstrate that a drug combination inhibiting these pathways may be a promising therapy for TNBC patients.

Biomimetic peptide display from a polymeric nanoparticle surface for targeting and antitumor activity to human triple-negative breast cancer cells.

While poly(lactic-co-glycolic acid)-block-polyethylene glycol (PLGA-PEG) nanoparticles (NPs) can encapsulate drug cargos and prolong circulation times, they show nonspecific accumulation in off-target tissues. Targeted delivery of drugs to tumor tissue and tumor vasculature is a promising approach for treating solid tumors while enhancing specificity and reducing systemic toxicity. AXT050, a collagen-IV derived peptide with both antitumor and antiangiogenic properties, is shown to bind to tumor-associated integrins with high affinity, which leads to targeted accumulation in tumor tissue. AXT050 conjugated to PLGA-PEG NPs at precisely controlled surface density functions both as a targeting agent to human tumor cells and demonstrates potential for simultaneous antitumorigenic and antiangiogenic activity. These targeted NPs cause inhibition of adhesion and proliferation in vitro when added to human triple-negative breast cancer cells and microvascular endothelial cells through binding to integrin αV ß3 . Furthermore, we find an in vivo biphasic relationship between tumor targeting and surface coating density of NPs coated with AXT050. NPs with an intermediate level of 10% peptide surface coating show approximately twofold greater accumulation in tumors and lower accumulation in the liver compared to nontargeted PLGA-PEG NPs in a murine biodistribution model. Display of biomimetic peptides from NP surfaces to both target and inhibit cancer cells has the potential to enhance the activity of cancer nanomedicines. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1753-1764, 2018.

Therapeutic potential of an anti-angiogenic multimodal biomimetic peptide in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a major cause of cancer-related death worldwide. Due to inadequate screening methods and the common coexistence of limited functional liver reserves, curative treatment options are limited. Liver transplantation is the only curative treatment modality for early HCC. There are multidisciplinary treatment options like ablative treatments, radiation and systemic therapy available for more advanced patients or those that are inoperable. Treatment resistance and progression is inevitable for these HCC patients. Newer therapeutics need to be explored for better management of HCC. HCC is a hypervascular tumor and many pro-angiogenic proteins are found significantly overexpressed in HCC. Here we explored the therapeutic potential of the anti-angiogenic, anti-lymphangiogenic, and directly anti-tumorigenic biomimetic collagen IV-derived peptide developed by our group. Human HCC cell lines HuH7, Hep3b and HepG2 showed significant disruption of cell adhesion and migration upon treatment with the peptide. Consistent with previously described multimodal inhibitory properties, the peptide was found to inhibit both c-Met and IGF1R signaling in HepG2 cells and blocked HepG2 conditioned media stimulation of microvascular endothelial cell (MEC) tube formation. Furthermore, the peptide treatment of mouse HepG2 tumor xenografts significantly inhibited growth relative to untreated controls. The peptide was also found to improve the survival of autochthonous Myc-induced HCC in a transgenic mouse model. Mechanistically, we found that the peptide treatment reduced microvascular density in the autochthonous liver tumors with increased apoptosis. This study shows the promising therapeutic potential of our biomimetic peptide in the treatment of HCC.

Crosstalk between stromal components and tumor cells of TNBC via secreted factors enhances tumor growth and metastasis.

Triple negative breast cancer (TNBC) as a metastatic disease is currently incurable. Reliable and reproducible methods for testing drugs against metastasis are not available. Stromal cells may play a critical role in tumor progression and metastasis. In this study, we determined that fibroblasts and macrophages secreted IL-8 upon induction by tumor cell-conditioned media (TCM) from MDA-MB-231 cancer cells. Our data showed that the proliferation of MDA-MB-231 cells co-cultured with fibroblasts or macrophages was enhanced compared to the monoculture. Furthermore, TNBC cell migration, a key step in tumor metastasis, was promoted by conditioned media (CM) from TCM-induced fibroblasts or macrophages. Knockdown of the IL-8 receptor CXCR2 by CRISPR-Cas9 reduces MDA-MB-231 cell proliferation and migration compared to wild type. In a mouse xenograft tumor model, the growth of MDA-MB-231-CXCR2-/- tumor was significantly decreased compared to the growth of tumors from wild-type cells. In addition, the incidence of thoracic metastasis of MDA-MB-231-CXCR2-/- tumors was reduced compared to wild type. We found that the auto- and paracrine loop exists between TNBC cells and stroma, which results in enhanced IL-8 secretion from the stromal components. Significantly, inhibition of the IL-8 signaling pathway by reparixin, an inhibitor of the IL-8 receptor, CXCR1/2, reduced MDA-MB-231 tumor growth and metastasis. Taken together, these findings implicate IL-8 signaling as a critical event in TNBC tumor growth and metastasis via crosstalk with stromal components.

An agent-based model of triple-negative breast cancer: the interplay between chemokine receptor CCR5 expression, cancer stem cells, and hypoxia.

BACKGROUND: Triple-negative breast cancer lacks estrogen, progesterone, and HER2 receptors and is thus not possible to treat with targeted therapies for these receptors. Therefore, a greater understanding of triple-negative breast cancer is necessary for the treatment of this cancer type. In previous work from our laboratory, we found that chemokine ligand-receptor CCL5-CCR5 axis is important for the metastasis of human triple-negative breast cancer cell MDA-MB-231 to the lymph nodes and lungs, in a mouse xenograft model. We collected relevant experimental data from our and other laboratories for numbers of cancer stem cells, numbers of CCR5+ cells, and cell migration rates for different breast cancer cell lines and different experimental conditions. RESULTS: Using these experimental data we developed an in silico agent-based model of triple-negative breast cancer that considers surface receptor CCR5-high and CCR5-low cells and breast cancer stem cells, to predict the tumor growth rate and spatio-temporal distribution of cells in primary tumors. We find that high cancer stem cell percentages greatly increase tumor growth. We find that anti-stem cell treatment decreases tumor growth but may not lead to dormancy unless all stem cells get eliminated. We further find that hypoxia increases overall tumor growth and treatment with a CCR5 inhibitor maraviroc slightly decreases overall tumor growth. We also characterize 3D shapes of solid and invasive tumors using several shape metrics. CONCLUSIONS: Breast cancer stem cells and CCR5+ cells affect the overall growth and morphology of breast tumors. In silico drug treatments demonstrate limited efficacy of incomplete inhibition of cancer stem cells after which tumor growth recurs, and CCR5 inhibition causes only a slight reduction in tumor growth.

Tyrosine kinase blocking collagen IV-derived peptide suppresses ocular neovascularization and vascular leakage.

Vascular endothelial growth factor (VEGF)-neutralizing proteins provide benefit in several retinal and choroidal vascular diseases, but some patients still experience suboptimal outcomes, and the need for frequent intraocular injections is a barrier to good outcomes. A mimetic peptide derived from collagen IV, AXT107, suppressed subretinal neovascularization (NV) in two mouse models predictive of effects in neovascular age-related macular degeneration (NVAMD) and inhibited retinal NV in a model predictive of effects in ischemic retinopathies. A combination of AXT107 and the current treatment aflibercept suppressed subretinal NV better than either agent alone. Furthermore, AXT107 caused regression of choroidal NV. AXT107 reduced the VEGF-induced vascular leakage that underlies macular edema in ischemic retinopathies and NVAMD. In rabbit eyes, which are closer to the size of human eyes, intraocular injection of AXT107 significantly reduced VEGF-induced vascular leakage by 86% at 1 month and 70% at 2 months; aflibercept significantly reduced leakage by 69% at 1 month and did not reduce leakage at 2 months, demonstrating the longer effectiveness of AXT107. AXT107 reduced ligand-induced phosphorylation of multiple receptors: VEGFR2, c-Met, and PDGFRß. Optimal signaling through these receptors requires complex formation with ß3 integrin, which was reduced by AXT107 binding to αvß3 AXT107 also reduced total VEGFR2 levels by increasing internalization, ubiquitination, and degradation. This biomimetic peptide is a sustained, multitargeted therapy that may provide advantages over intraocular injections of specific VEGF-neutralizing proteins.

Analysis of gene expression of secreted factors associated with breast cancer metastases in breast cancer subtypes.

Breast cancer is a heterogeneous disease, having multiple subtypes with different malignant phenotypes. The triple-negative breast cancer, or basal breast cancer, is highly aggressive, metastatic, and difficult to treat. Previously, we identified that key molecules (IL6, CSF2, CCL5, VEGFA, and VEGFC) secreted by tumor cells and stromal cells in basal breast cancer can promote metastasis. It remains to assess whether these molecules function similarly in other subtypes of breast cancer. Here, we characterize the relative gene expression of the five secreted molecules and their associated receptors (GP130, GMRA, GMRB, CCR5, VEGFR2, NRP1, VEGFR3, NRP2) in the basal, HER2 (human epidermal growth factor receptor 2) positive, luminal A, and luminal B subtypes using high throughput data from tumor samples in The Cancer Genome Atlas (TCGA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC). IL6 and CCL5 gene expression are basal breast cancer specific, whereas high gene expression of GP130 was observed in luminal A/B. VEGFA/C and CSF2 mRNA are overexpressed in HER2 positive breast cancer, with VEGFA and CSF2 also overexpressed in basal breast cancer. Further study of the specific protein function of these factors within their associated cancer subtypes may yield personalized biomarkers and treatment modalities.

Heterogeneity of chemokine cell-surface receptor expression in triple-negative breast cancer.

INTRODUCTION: Tumor heterogeneity is a well-established concept in cancer research. In this paper, we examine an additional type of tumor cell heterogeneity - tumor cell-surface receptor heterogeneity. METHODS: We use flow cytometry to measure the frequency and numbers of cell-surface receptors on triple negative breast cancer cell lines. RESULTS: We find two distinct populations of human triple-negative breast cancer cells MDA-MB-231 when they are grown in culture, one with low surface levels of various chemokine receptors and a second with much higher levels. The population with high surface levels of these receptors is increased in the more metastatic MDA-MB-231-luc-d3h2ln cell line. CONCLUSION: We hypothesize that this high cell-surface receptor population is involved in metastasis. We find that the receptor high populations can be modulated by tumor conditioned media and IL6 treatment indicating that the tumor microenvironment is important for the maintenance and sizes of these populations.