Sequential targeted delivery of paclitaxel and camptothecin using a cross-linked "nanosponge" network for lung cancer chemotherapy.

The applicability of a HVGGSSV peptide targeted "nanosponge" drug delivery system for sequential administration of a microtubule inhibitor (paclitaxel) and topoisomerase I inhibitor (camptothecin) was investigated in a lung cancer model. Schedule-dependent combination treatment with nanoparticle paclitaxel (NP PTX) and camptothecin (NP CPT) was studied in vitro using flow cytometry and confocal imaging to analyze changes in cell cycle, microtubule morphology, apoptosis, and cell proliferation. Results showed significant G2/M phase cell cycle arrest, changes in microtubule dynamics that produced increased apoptotic cell death and decreased proliferation with initial exposure to NP PTX, followed by NP CPT in lung cancer cells. In vivo molecular imaging and TEM studies validated HVGGSSV-NP tumor binding at 24 h and confirmed the presence of Nanogold labeled HVGGSSV-NPs in tumor microvascular endothelial cells. Therapeutic efficacy studies conducted with sequential HVGGSSV targeted NP PTX and NP CPT showed 2-fold greater tumor growth delay in combination versus monotherapy treated groups, and 4-fold greater delay compared to untargeted and systemic drug controls. Analytical HPLC/MS methods were used to quantify drug content in tumor tissues at various time points, with significant paclitaxel and camptothecin levels in tumors 2 days postinjection and continued presence of both drugs up to 23 days postinjection. The efficacy of the NP delivery system in sequential treatments was corroborated in both in vitro and in vivo lung cancer models showing increased G2/M phase arrest and microtubule disruption, resulting in enhanced apoptotic cell death, decreased cell proliferation and vascular density.

Human Recombinant Alkaline Phosphatase (Ilofotase Alfa) Protects Against Kidney Ischemia-Reperfusion Injury in Mice and Rats Through Adenosine Receptors.

Adenosine triphosphate (ATP) released from injured or dying cells is a potent pro-inflammatory "danger" signal. Alkaline phosphatase (AP), an endogenous enzyme that de-phosphorylates extracellular ATP, likely plays an anti-inflammatory role in immune responses. We hypothesized that ilofotase alfa, a human recombinant AP, protects kidneys from ischemia-reperfusion injury (IRI), a model of acute kidney injury (AKI), by metabolizing extracellular ATP to adenosine, which is known to activate adenosine receptors. Ilofotase alfa (iv) with or without ZM241,385 (sc), a selective adenosine A2A receptor (A2AR) antagonist, was administered 1 h before bilateral IRI in WT, A2AR KO (Adora2a-/- ) or CD73-/- mice. In additional studies recombinant alkaline phosphatase was given after IRI. In an AKI-on-chronic kidney disease (CKD) ischemic rat model, ilofotase alfa was given after the three instances of IRI and rats were followed for 56 days. Ilofotase alfa in a dose dependent manner decreased IRI in WT mice, an effect prevented by ZM241,385 and partially prevented in Adora2a-/- mice. Enzymatically inactive ilofotase alfa was not protective. Ilofotase alfa rescued CD73-/- mice, which lack a 5'-ectonucleotidase that dephosphorylates AMP to adenosine; ZM241,385 inhibited that protection. In both rats and mice ilofotase alfa ameliorated IRI when administered after injury, thus providing relevance for therapeutic dosing of ilofotase alfa following established AKI. In an AKI-on-CKD ischemic rat model, ilofotase alfa given after the third instance of IRI reduced injury. These results suggest that ilofotase alfa promotes production of adenosine from liberated ATP in injured kidney tissue, thereby amplifying endogenous mechanisms that can reverse tissue injury, in part through A2AR-and non-A2AR-dependent signaling pathways.

Correlation of quantified contrast-enhanced sonography with in vivo tumor response.

OBJECTIVE: The purpose of our study was to establish in vivo criteria for monitoring tumor treatment response using 3-dimensional (3D) volumetric gray scale, power Doppler, and contrast-enhanced sonography. METHODS: Twelve mice were implanted with Lewis lung carcinoma cells on their hind limbs and categorized to 4 groups: control, chemotherapy, radiation therapy, and chemoradiation. A high-frequency ultrasound system with a 40-MHz probe was used to image the tumors. Follow-up contrast-enhanced sonography was performed on days 7 and 14 of treatment with two 50-microL boluses of a perflutren microbubble contrast agent injected into the tail vein. The following contrast-enhanced sonographic criteria were quantified: time to peak, peak intensity, alpha (microvessel cross-sectional area), and beta (microbubble velocity). Three-dimensional power Doppler images were also obtained after the acquisition of contrast data. On day 15, the tumors were excised for immunohistochemical analysis with CD31 fluorescent staining. RESULTS: The tumor size and 3D power Doppler vascular index showed no statistically significant correlation with microvascular density in all examined groups. Among all of the analyzed contrast-enhanced sonographic parameters, relative alpha showed the strongest correlation with the histologic microvessel density (Pearson r = 0.93; P < .01) and an independent association with the histologic data in a multiple regression model (beta = .93; R(2) = 0.86; P < .01). CONCLUSIONS: Of the various examined sonographic parameters, alpha has the strongest correlation with histologic microvessel density and may be the parameter of choice for the noninvasive monitoring of tumor angiogenic response in vivo.

Multifunctional FePt nanoparticles for radiation-guided targeting and imaging of cancer.

A multifunctional FePt nanoparticle was developed that targets tumor microvasculature via "radiation-guided" peptides, and is detected by both near-infrared (NIR) fluorescence imaging and analytical mass spectrometry methods. Tumor specific binding was first measured by biotinylated peptide linked to fluorophore-conjugated streptavidin. This showed tumor selective binding to tumors using the HVGGSSV peptide. FePt nanoparticles were synthesized sequentially by surface modification with poly(L)lysine, poly(ethylene) glycol conjugation, and functionalized with HVGGSSV peptide and fluorescent probe Alexa fluor 750. NIR fluorescence imaging and ICP-MS analysis showed significant HVGGSSV-FePt nanoparticle binding to irradiated tumors as compared to unirradiated tumors and controls. Results indicate that multifunctional FePt nanoparticles have potential application for radiation-guided targeting and imaging of cancer.

Radiation-guided drug delivery to mouse models of lung cancer.

PURPOSE: The purpose of this study was to achieve improved cancer-specific delivery and bioavailability of radiation-sensitizing chemotherapy using radiation-guided drug delivery. EXPERIMENTAL DESIGN: Phage display technology was used to isolate a recombinant peptide (HVGGSSV) that binds to a radiation-inducible receptor in irradiated tumors. This peptide was used to target nab-paclitaxel to irradiated tumors, achieving tumor-specificity and enhanced bioavailability of paclitaxel. RESULTS: Optical imaging studies showed that HVGGSSV-guided nab-paclitaxel selectively targeted irradiated tumors and showed 1.48 ± 1.66 photons/s/cm(2)/sr greater radiance compared with SGVSGHV-nab-paclitaxel, and 1.49 ± 1.36 photons/s/cm(2)/sr greater than nab-paclitaxel alone (P < 0.05). Biodistribution studies showed >5-fold increase in paclitaxel levels within irradiated tumors in HVGGSSV-nab-paclitaxel-treated groups as compared with either nab-paclitaxel or SGVSGHV-nab-paclitaxel at 72 hours. Both Lewis lung carcinoma and H460 lung carcinoma murine models showed significant tumor growth delay for HVGGSSV-nab-paclitaxel as compared with nab-paclitaxel, SGVSGHV-nab-paclitaxel,and saline controls. HVGGSSV-nab-paclitaxel treatment induced a significantly greater loss in vasculature in irradiated tumors compared with unirradiated tumors, nab-paclitaxel, SGVSGHV-nab-paclitaxel, and untreated controls. CONCLUSIONS: HVGGSSV-nab-paclitaxel was found to bind specifically to the tax-interacting protein-1 (TIP-1) receptor expressed in irradiated tumors, enhance bioavailability of paclitaxel, and significantly increase tumor growth delay as compared with controls in mouse models of lung cancer. Here we show that targeting nab-paclitaxel to radiation-inducible TIP-1 results in increased tumor-specific drug delivery and enhanced biological efficacy in the treatment of cancer.