RGD-modifided oncolytic adenovirus exhibited potent cytotoxic effect on CAR-negative bladder cancer-initiating cells

Cancer-initiating cell (CIC) is critical in cancer development, maintenance and recurrence. The reverse expression pattern of coxsackie and adenovirus receptor (CAR) and α_ν integrin in bladder cancer decreases the infection efficiency of adenovirus. We constructed Arg-Gly-Asp (RGD)-modified oncolytic adenovirus, carrying EGFP or TNF-related apoptosis-inducing ligand (TRAIL) gene (Onco^Ad.RGD-hTERT-EGFP/TRAIL), and applied them to CAR-negative bladder cancer T24 cells and cancer-initiating T24 sphere cells. Onco^Ad.RGD-hTERT-EGFP had enhanced infection ability and cytotoxic effect on T24 cells and T24 sphere cells, but little cytoxicity on normal urothelial SV-HUC-1 cells compared with the unmodified virus Onco^Ad.hTERT-EGFP. Notably, Onco^Ad.RGD-hTERT-TRAIL induced apoptosis in T24 cells and T24 sphere cells. Furthermore, it completely inhibited xenograft initiation established by the oncolytic adenovirus-pretreated T24 sphere cells, and significantly suppressed tumor growth by intratumoral injection. These results provided a promising therapeutic strategy for CAR-negative bladder cancer through targeting CICs.

Integrin-targeted pH-responsive micelles for enhanced efficiency of anticancer treatment in vitro and in vivo

The key to developing more nanocarriers for the delivery of drugs in clinical applications is to consider the route of the carrier from the administration site to the target tissue and to look for a simple design to complete this whole journey. We synthesized the amphiphilic copolymer cRGDfK-poly(ethylene glycol)-b-poly(2,4,6-trimethoxybenzylidene-1,1,1-tris(hydroxymethyl) ethane methacrylate) (cRGD-PETM) to construct multifunctional micelles. These micelles combined enhanced drug-loading efficiency with tumor-targeting properties, visual detection and controllable intracellular drug release, resulting in an improved chemotherapeutic effect in vivo. Doxorubicin (DOX) was encapsulated within the cRGD-PETM micelles as a model drug (termed as cRGD-PETM/DOX Ms). The size and morphology of the micelles were characterized systematically. As a result of the hydrophobic interaction and the π-π conjugation between the DOX molecules and the PTTMA copolymers, the cRGD-PETM/DOX Ms showed an excellent drug-loading capacity. The results of in vitro drug-release studies indicated that the cumulative release of DOX from cRGD-PETM/DOX Ms at pH 5.0 was twice that at pH 7.4. The results of fluorescent microscopic analysis showed that the cRGD-PETM/DOX Ms could be internalized by 4T1 and HepG2 cells via receptor-mediated endocytosis with rapid intracellular drug release, which resulted in increased cytotoxicity compared with free DOX. Ex vivo imaging studies showed that the cRGD-PETM/DOX Ms improved the accumulation and retention of the drug in tumor tissues. Studies of the in vivo anticancer effects showed that the cRGD-PETM/DOX Ms had a significantly higher therapeutic efficacy with lower side-effects than free DOX and PETM/DOX Ms. These results show that the multifunctional cRGD-PETM/DOX Ms have great potential as vehicles for the delivery of hydrophobic anticancer drugs.

Dynamic biostability, biodistribution, and toxicity of L/D-peptide-based supramolecular nanofibers

Self-assembling peptide nanofibers (including naturally L-amino acid-based and unnaturally D-amino acid-based ones) have been widely utilized in biomedical research. However, there has been no systematic study on their in vivo stability, distribution, and toxicity. Herein we systematically study the in vivo dynamic biostability, biodistribution, and toxicity of supramolecular nanofibers formed by Nap-GFFYGRGD (L-amino acid-based, L-fibers) and Nap-G(D)F(D)F(D)YGRGD (D-amino acid-based, D-fibers), respectively. The D-fibers have better in vitro and in vivo biostabilities than L-fibers. It is found that D-fibers keep a good integrity in plasma during 24 h, while half of l-fibers are digested upon incubation in plasma for 6 h. The biodistributions of L- and D-fibers are also studied using the iodine-125 radiolabeling technique. The results reveal that L-fibers mainly accumulate in stomach, whereas d-fibers preferentially distribute in liver. Successive administrations of both L- and D-fibers with the dose of 30 mg/kg/dose cause no significant inflammation, liver and kidney function damages, immune reaction, and dysfunction of hematopoietic system. This study will provide fundamental guidelines for utilization of self-assembling peptide-based supramolecular nanomaterials in biomedical applications, such as drug delivery, bioimaging, and regenerative medicine.

Restless legs syndrome: an underappreciated and distressing problem for haemodialysis patients

Restless legs syndrome is a distressing condition that is more common in patients with end-stage renal failure. Despite the significant impact it has on quality of life and the documented association between restless legs syndrome and increased mortality, limited data regarding the epidemiology of restless legs syndrome in Australian dialysis patients are available. We report a prospective study that assessed the prevalence and factors associated with restless legs syndrome in an in-centre haemodialysis population.

Self-regulated multifunctional collaboration of targeted nanocarriers for enhanced tumor therapy

Exploring ideal nanocarriers for drug delivery systems has encountered unavoidable hurdles, especially the conflict between enhanced cellular uptake and prolonged blood circulation, which have determined the final efficacy of cancer therapy. Here, based on controlled self-assembly, surface structure variation in response to external environment was constructed toward overcoming the conflict. A novel micelle with mixed shell of hydrophilic poly(ethylene glycol) PEG and pH responsive hydrophobic poly(β-amino ester) (PAE) was designed through the self-assembly of diblock amphiphilic copolymers. To avoid the accelerated clearance from blood circulation caused by the surface exposed targeting group c(RGDfK), here c(RGDfK) was conjugated to the hydrophobic PAE and hidden in the shell of PEG at pH 7.4. At tumor pH, charge conversion occurred, and c(RGDfK) stretched out of the shell, leading to facilitated cellular internalization according to the HepG2 cell uptake experiments. Meanwhile, the heterogeneous surface structure endowed the micelle with prolonged blood circulation. With the self-regulated multifunctional collaborated properties of enhanced cellular uptake and prolonged blood circulation, successful inhibition of tumor growth was achieved from the demonstration in a tumor-bearing mice model. This novel nanocarrier could be a promising candidate in future clinical experiments.

Synthesis, biodistribution, and imaging of PEGylated-acetylated polyamidoamine dendrimers

Polyamidoamine (PAMAM) dendrimers have been widely used as drug carriers, non-viral gene vectors and imaging agents. However, the use of dendrimers in biological system is constrained because of inherent toxicity and organ accumulation. In this study, the strategy of acetylation and PEGylation-acetylation was used to minimize PAMAM dendrimers toxicities and to improve their biodistribution and pharmacokinetics for medical application. PEGylated-acetylated PAMAM (G4-Ac-PEG) dendrimers were synthesized by PEGylation of acetylated PAMAM dendrimer of generation 4 (G4) with acetic anhydride and polyethylene glycol (PEG) 3.4 k. To investigate the cytotoxicity and in vivo biodistribution of the conjugates, in vitro cell viability analysis, Iodine-125 (125I) imaging, tissue distribution and hematoxylin-eosin (HE) staining were performed. We find that acetylation and PEGylation-acetylation essentially eliminates the inherent dendrimer cytotoxicity in vitro. Planar gamma (gamma) camera imaging revealed that all the conjugates were slowly eliminated from the body, and higher abdominal accumulation of acetylation PAMAM dendrimer was observed. Tissue distribution analysis showed that PEGylated-acetylated dendrimers have longer blood retention and lower accumulation in organs such as the kidney and liver than the non-PEGylated-acetylated dendrimers, but acetylation only can significantly increase the accumulation of G4 in the kidney and decrease the concentration in blood. Histology results reveal that no obvious damage was observed in all groups after high dose administration. This study indicates that PEGylation-acetylation could improve the blood retention, decrease organ accumulation, and improve pharmacokinetic profile, which suggests that PEGylation-acetylation provides an alternative method for PAMAM dendrimers modification.

Self-assembling peptide of D-amino acids boosts selectivity and antitumor efficacy of 10-hydroxycamptothecin

D-peptides, which consist of D-amino acids and can resist the hydrolysis catalyzed by endogenous peptidases, are one of the promising candidates for construction of peptide materials with enhanced biostability in vivo. In this paper, we report on a self-assembling supramolecular nanostructure of D-amino acid-based peptide Nap-G(D)F(D)F(D)YGRGD (D-fiber, (D)F meant D-phenylalanine, (D)Y meant D-tyrosine), which were used as carriers for 10-hydroxycamptothecin (HCPT). Transmission electron microscopy observations demonstrated the filamentous morphology of the HCPT-loaded peptides (d-fiber-HCPT). The better selectivity and antitumor activity of D-fiber-HCPT than L-fiber-HCPT were found in the in vitro and in vivo antitumor studies. These results highlight that this model D-fiber system holds great promise as vehicles of hydrophobic drugs for cancer therapy.

The effect of puberty on fat oxidation rates during exercise in overweight and normal-weight girls

Excess weight is often associated with insulin resistance (IR) and may disrupt fat oxidation during exercise. This effect is further modified by puberty. While studies have shown that maximal fat oxidation rates (FOR) during exercise decrease with puberty in normal-weight (NW) and overweight (OW) boys, the effect of puberty in NW and OW girls is unclear. Thirty-three NW and OW girls ages 8–18 yr old completed a peak aerobic capacity test on a cycle ergometer. FOR were calculated during progressive submaximal exercise. Body composition and Tanner stage were determined. For each participant, a best-fit polynomial curve was constructed using fat oxidation vs. exercise intensity to estimate max FOR. In a subset of the girls, IR derived from an oral glucose tolerance test ( n = 20), and leptin and adiponectin levels ( n = 11) were assessed in relation to FOR. NW pre-early pubertal girls had higher max FOR [6.9 ± 1.4 mg·kg fat free mass (FFM)−1·min−1] than NW mid-late pubertal girls (2.2 ± 0.9 mg·kg FFM−1·min−1) ( P = 0.002), OW pre-early pubertal girls (3.8 ± 2.1 mg·kg FFM−1·min−1), and OW mid-late pubertal girls (3.3 ± 0.9 mg·kg FFM−1·min−1) ( P < 0.05). Bivariable analyses showed positive associations between FOR with homeostatic model assessment of IR ( P = 0.001), leptin ( P < 0.001), and leptin-to-adiponectin ratio ( P = 0.001), independent of percent body fat. Max FOR decreased in NW girls during mid-late puberty; however, this decrease associated with puberty was blunted in OW girls due to lower FOR in pre-early puberty. The presence of IR due to obesity potentially masks the effect of puberty on FOR during exercise in girls.

Novel tumor-targeting, self-assembling peptide nanofiber as a carrier for effective curcumin delivery

The poor aqueous solubility and low bioavailability of curcumin restrict its clinical application for cancer treatment. In this study, a novel tumor-targeting nanofiber carrier was developed to improve the solubility and tumor-targeting ability of curcumin using a self-assembled Nap-GFFYG-RGD peptide. The morphologies of the peptide nanofiber and the curcumin-encapsulated nanofiber were visualized by transmission electron microscopy. The tumor-targeting activity of the curcumin-encapsulated Nap-GFFYG-RGD peptide nanofiber (f-RGD-Cur) was studied in vitro and in vivo, using Nap-GFFYG-RGE peptide nanofiber (f-RGE-Cur) as the control. Curcumin was encapsulated into the peptide nanofiber, which had a diameter of approximately 10-20 nm. Curcumin showed sustained-release behavior from the nanofibers in vitro. f-RGD-Cur showed much higher cellular uptake in αvβ3 integrin-positive HepG2 liver carcinoma cells than did non-targeted f-RGE-Cur, thereby leading to significantly higher cytotoxicity. Ex vivo studies further demonstrated that curcumin could accumulate markedly in mouse tumors after administration of f-RGD-Cur via the tail vein. These results indicate that Nap-GFFYG-RGD peptide self-assembled nanofibers are a promising hydrophobic drug delivery system for targeted treatment of cancer.

The impact of PEGylation patterns on the in vivo biodistribution of mixed shell micelles

Polyethylene glycol (PEG)-ylation is a widely used strategy to fabricate nanocarriers with a long blood circulation time. Further elaboration of the contribution of the surface PEGylation pattern to biodistribution is highly desirable. We fabricated a series of polyion complex (PIC) micelles PEGylated with different ratios (PEG2k and PEG550). The plasma protein adsorption, murine macrophage uptake, and in vivo biodistribution with iodine-125 as the tracer were systematically studied to elucidate the impact of PEGylation patterns on the biodistribution of micelles. We demonstrated that the PEGylated micelles with short hydrophilic PEG chains mixed on the surface were cleared quickly by the reticuloendothelial system (RES), and the single PEG2k PEGylated micelles could efficiently prolong the blood circulation time and increase their deposition in tumor sites. The present study extends the understanding of the PEGylation strategy to further advance the development of ideal nanocarriers for drug delivery and imaging applications.

In vivo biodistribution of mixed shell micelles with tunable hydrophilic/hydrophobic surface

The miserable targeting performance of nanocarriers for cancer therapy arises largely from the rapid clearance from blood circulation and the major accumulation in the organs of the reticuloendothelial system (RES), leading to inefficient enhanced permeability and retention (EPR) effect after intravenous injection (i.v.). Herein, we reported an efficient method to prolong the blood circulation of nanoparticles and decrease their deposition in liver and spleen. In this work, we fabricated a series of mixed shell micelles (MSMs) with approximately the same size, charge and core composition but with varied hydrophilic/hydrophobic ratios in the shell through spontaneously self-assembly of block copolymers poly(ethylene glycol)-block-poly(l-lysine) (PEG-b-PLys) and poly(N-isopropylacrylamide)-block-poly(aspartic acid) (PNIPAM-b-PAsp) in aqueous medium. The effect of the surface heterogeneity on the in vivo biodistribution was systematically investigated through in vivo tracking of the (125)I-labeled MSMs determined by Gamma counter. Compared with single PEGylated micelles, some MSMs were proved to be significantly efficient with more than 3 times lower accumulation in liver and spleen and about 6 times higher concentration in blood at 1 h after i.v.. The results provide us a novel strategy for future development of long-circulating nanocarriers for efficient cancer therapy.

In Vivo and In Vitro Silica Induces Nuclear Factor Egr-1 Activation Mediated by ERK 1/2 in RAW264.7 Cell Line

The transcription factor early growth response gene (Egr-1) is a stress response gene activated by various forms of stress. The effect of silica on transcription and expression of Egr-1 was investigated in rat lung and in RAW264.7 cells. Silica induced the expression of Egr-1 in vivo and was mainly located in alveolar macrophage cells and lung epithelial cells. Furthermore, silica induced Egr-1 mRNA and protein expression in cultured RAW264.7 cells. Immunofluorescence microscopy revealed translocation of Egr-1 to the nucleus in response to silica. The contribution of the extracellular signal-regulated kinase (ERK) pathway to the activation of Egr-1 in response to silica was examined. Exposure to silica resulted in a rapid phosphorylation of ERK 1/2 kinases in RAW264.7 cells. MAP Kinase Kinase (MEK) inhibitor U0126 prevented Egr-1 induction by silica. The results suggest that silica could induce Egr-1 activation in macrophages in vivo and in vitro and that phosphorylated ERK 1/2 may be involved in this action.

Silica Induces Plasminogen Activator Inhibitor-1 Expression through a MAPKs/AP-1-Dependent Mechanism in Human Lung Epithelial Cells

ABSTRACT Plasminogen activator inhibitor-1 (PAI-1) plays an important role in the silica-induced pulmonary fibrosis. The effect of silica on the expression of PAI-1 was investigated in human lung epithelial cells (A549). Silica induced PAI-1 expression in a concentration-(50-200 mug/mL) and time-(4-24 h) dependent manner in A549 cells. Furthermore, the roles of mitogen-activated protein kinase (MAPK)/activator protein-1 (AP-1) signaling pathways in silica-induced PAI-1 expression were examined. We found that silica (200 mug/mL) treatment for 4 to 24 h resulted in AP-1 activation in A549 cells. Cells were pretreated with the AP-1 inhibitor curcumin (10, 25, 50 muM), and silica-induced PAI-1 expression was reduced by 20%, 63%, and 65%, respectively. In addition, dominant-negative mutant c-Jun (TAM67) down-regulated silica-induced PAI-1 expression by 59%. P38 kinase inhibitor SB203580 (20 muM) and Erk inhibitor PD98059 (50 muM) suppressed silica-induced PAI-1 expression by 35% and 51%, respectively. Additionally, PD98059 but not SB203580 inhibited the AP-1 DNA binding activity induced by silica. The results suggest that the PAI-1 expression induced by silica may be involved in the activation of MAPKs/AP-1 signaling pathways in human lung epithelial cells.

Engineering dynamics of growth factors and other therapeutic ligands

Peptide growth factors and other receptor-binding cytokine ligands are of interest in contemporary molecular health care approaches in applications such as wound healing, tissue regeneration, and gene therapy. Development of effective technologies based on operation of these regulatory molecules requires an ability to deliver the ligands to target cells in a reliable and well-characterizable manner. Quantitative information concerning the fate of peptide ligands within tissues is necessary for adequate interpretation of experimental observations at the tissue level and for truly rational engineering design of ligand-based therapies. To address this need, we are undertaking efforts to elucidate effects of key molecular and cellular parameters on temporal and spatial distribution of cytokines in cell population and cell/matrix systems. In this article we summarize some of our recent findings on dynamics of growth factor depletion by cellular endocytic trafficking, growth factor transport through cellular matrices, and growth factor production and release by autocrine cell systems. (c) 1996 John Wiley & Sons, Inc.

OT1-02-05: A Phase III Clinical Trial Comparing Trastuzumab Given Concurrently with Radiation Therapy to Radiation Therapy (RT) Alone for Women with HER2−Positive DCIS Resected by Lumpectomy: NSABP B-43

Background

Because a substantial portion of DCIS is ER negative and overexpresses HER2, therapy targeting this protein is a promising strategy for HER2−overexpressing DCIS.

Preclinical studies have shown that trastuzumab (T) boosts the effectiveness of RT in xenograft models and in cell lines with no detrimental effect on irradiated HER2−normal cells. Studies correlating clinical response with molecular markers in T-treated patients show that apoptosis occurs within 1 wk of starting singleagent T, with little effect on proliferation. Shorter duration treatments with this agent require investigation. Adjuvant trials using T during breast irradiation have already provided ample safety evidence. Will T administered during WBI improve lumpectomy + WBI results in women with HER2−positive DCIS? This trial will allow us to better understand the biology of breast cancer and its prevention and will extend the benefits of breast-conserving surgery for women with DCIS.

Trial Design: Post lumpectomy for DCIS without evidence of an invasive component, a central review of each patient's pure DCIS lesion is carried out for HER2 by IHC analysis. If the HER2 is 2+, FISH analysis is done, and patients whose tumors are HER2 3+ or FISH positive can be randomly assigned to receive 2 doses of T 3 wk apart during WBI or to receive WBI alone.

Eligibility criteria: Women 18 years or older with an ECOG status of 0 or 1 who have undergone a margin-clear lumpectomy for DCIS and whose tumors are clinically or pathologically node negative are eligible. DCIS must be HER2 positive by central testing. ER and/or PR status must be known before random assignment.

Specific aims: The primary aim is to determine if T given concurrently with WBI is more beneficial in preventing IBC recurrence, ipsilateral skin cancer recurrence, or ipsilateral DCIS compared with WBI alone for HER2−positive DCIS resected by lumpectomy. Secondary aims are to compare the possible benefit of T given during WBI to that of WBI alone in preventing regional or distant recurrence and contralateral invasive or DCIS breast cancer. B-43 will determine if invasive or DCIS DFS, recurrence-free interval, and OS can be improved with the addition of T to WBI. The effects of T on ovarian function in premenopausal women will also be assessed.

Statistical methods and accrual: Our design calls for accrual of 2000 patients during a 7.9-year period. As of May 31, 2011, 578 patients have been entered. A definitive analysis of primary endpoints will be performed when 163 ipsilateral breast cancer events occur (7.5 and 8 years after protocol initiation). This number of events affords 80% power to detect a hazard reduction of 36%, from 1.73 ipsilateral breast cancer events per 100 patient-years to 1.11 events per 100 patient-years. The 36% observed reduction in the hazard of IIBCR-SCR-DCIS on the T arm is based on a projection of 40% hazard reduction if the compliance were perfect, with a 10% noncompliance rate.

Supported by PHS grants NCI-U10-CA-69651, NCI-U10-CA-12027, and NCI P30-CA-14599 from the US NCI and Genentech, Inc.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT1-02-05.

Endocytic Relay as a Potential Means for Enhancing Ligand Transport through Cellular Tissue Matrices: Analysis and Possible Implications for Drug Delivery

The transport of peptide ligands, such as cytokines, through tissue is complicated by resistances due to cell multilayers and holdup in extracellular matrix. To determine whether it is possible for receptor-mediated endocytic trafficking to enhance ligand transport, we have developed a mathematical model of ligand flux through tissue containing cells possessing complementary receptors. Tissue is considered as two phases: the cell phase and the matrix phase; thus tissue is modeled as analogous to a packed bed reactor. This model allows calculation of steady-state flux of intact and degraded peptide through a one-dimensional cell/tissue matrix. Both environmental and molecular parameters were considered in this study. Results predict that three quantities should have a major influence on growth factor flux: the ratio of matrix diffusivity to intracellular "diffusivity" (D(m)/D(i)), the extracellular matrix proteolysis rate constant (k (prot)), and the fraction of internalized growth factor degraded (f(1)). For basal levels of intracellular degradation (0 < f(1) >/= 0.05) but no extracellular proteolysis, significant enhancement is possible only for D(m)/D(i) >/=1. f(1) increases, enhancement is only possible up to f(1)= 0.07 even for D(m)/D(i) < 1. For significant levels of extracellular proteolysis (k (prot) > 0), the requirements for D(m)/D(i) and f(1) to permit transport enhancement encompass a broader range with the exact values dependent on k (prot). These insights may be helpful for delivery of ligands generated from controlled-release devices or genetically modified autocrine cells, and may also provide better understanding of cytokine transport in embryonic development.