Dual mechanistic TRAIL nanocarrier based on PEGylated heparin taurocholate and protamine which exerts both pro-apoptotic and anti-angiogenic effects.

The selective cytotoxicity of tumor necrosis factor-related apoptosis inducing ligand (TRAIL) to cancer cells but not to normal cells makes it an attractive candidate for cancer therapeutics. However, the disadvantages of TRAIL such as physicochemical instability and short half-life limit its further clinical applications. In this study, TRAIL was encapsulated into a novel anti-angiogenic nanocomplex for both improved drug distribution at the tumor site and enhanced anti-tumor efficacy. A nanocomplex was prepared firstly by entrapping TRAIL into PEG-low molecular weight heparin-taurocholate conjugate (LHT7), which is previously known as a potent angiogenesis inhibitor. Then, protamine was added to make a stable form of nanocomplex (PEG-LHT7/TRAIL/Protamine) by exerting electrostatic interactions. We found that entrapping TRAIL into the nanocomplex significantly improved both pharmacokinetic properties and tumor accumulation rate without affecting the tumor selective cytotoxicity of TRAIL. Furthermore, the anti-tumor efficacy of nanocomplex was highly augmented (73.77±4.86%) compared to treating with only TRAIL (18.49 ± 19.75%), PEG-LHT7/Protamine (47.84 ± 14.20%) and co-injection of TRAIL and PEG-LHT7/Protamine (56.26 ± 9.98%). Histological analysis revealed that treatment with the nanocomplex showed both anti-angiogenic efficacy and homogenously induced cancer cell apoptosis, which suggests that accumulated TRAIL and LHT7 in tumor tissue exerted their anti-tumor effects synergistically. Based on this study, we suggest that PEG-LHT7/Protamine complex is an effective nanocarrier of TRAIL for enhancing drug distribution as well as improving anti-tumor efficacy by exploiting the synergistic mechanism of anti-angiogenesis.

Conserving the lymphatics from the arm using fluorescence imaging in patients with breast cancer at high risk of postoperative lymphedema: a pilot study.

BACKGROUND: Postoperative lymphedema in breast cancer survivors is a serious complication that develops from axillary lymph node dissection (ALND), chemotherapy, and radiation therapy. Axillary reverse mapping (ARM) was recently introduced to reduce lymphedema. This pilot study aimed to investigate the feasibility of preserving the ARM node using fluorescence imaging for patients at high risk of lymphedema. METHODS: We prospectively screened patients with breast cancer who had pathologic node-positive disease at diagnosis and were scheduled for neoadjuvant chemotherapy (NCT). The sentinel lymph node (SLN) was identified using blue dye and radioisotope, while the ARM node was traced using indocyanine green (ICG). In cases in which SLN was negative on the intraoperative frozen section examination, the ARM node and lymphatics were preserved. RESULTS: Of the 20 screened patients, six whose metastatic axillary lymph node (ALN) was converted to clinically node-negative disease after NCT were enrolled. No patients experienced recurrence at 24 months postoperative. Four patients who had a preserved ARM node did not develop lymphedema. One patient whose ARM node was not preserved due to SLN identification failure did not develop postoperative lymphedema. One patient who underwent ALND without ARM node conservation because of metastatic SLN on frozen section examination developed postoperative lymphedema. CONCLUSIONS: ARM is oncologically safe, decreases the incidence of postoperative lymphedema, and allows for the early detection of postoperative lymphedema in patients who underwent ALND. Ultimately, ARM may help improve the quality of life of patients with pathologic node-positive breast cancer.

Utilization of bioelectrical impedance analysis for detection of lymphedema in breast Cancer survivors: a prospective cross sectional study.

BACKGROUND: Breast cancer survivors are at risk of developing breast cancer-related lymphedema (BCRL) after surgical treatment, which may have a negative effect on quality of life. The purpose of this study was to investigate the clinical role of bioelectrical impedance analysis (BIA) and the relationship between the development of BCRL in breast cancer survivors who have undergone axillary surgery. METHODS: A total of 228 patients with breast cancer were enrolled in the study between May 2016 and January 2017. BCRL was assessed by measuring the circumference of both arms at 15 cm below the acromion process and the olecranon process. Patients were classified as BCRL (n = 22) and non-BCRL (n = 206) based on the difference of the arm circumference of 2 cm. Data including lymphedema, anthropometry, BIA measurements, food frequency questionnaire, type of surgery, total number of dissected lymph nodes, and post-operative treatment were collected. RESULTS: Of the breast cancer survivors, 10.4% had BCRL by the definition. The BCRL group contained 22 patients, while the non-BCRL group contained 206 patients. Compared to the non-BCRL group, the BCRL group had a higher body mass index, a larger percentage of ideal body weight, more dissected lymph nodes, and higher single frequency BIA (SFBIA) ratio (P = 0.027, P = 0.031, P < 0.001, and P < 0.001, respectively). The SFBIA ratio provided 63.64% sensitivity and 95.15% specificity in estimating the risk of BCRL. CONCLUSION: Our data provides evidence to support that the use of SFBIA ratio can serve as an alternative method to monitor and/or diagnose BCRL. TRIAL REGISTRATION: This trial was retrospectively registered at Clinicaltrials.gov identifier ( NCT03391206 ) on the 5 January 2018.

Effect of primary tumor resection on overall survival in patients with stage IV breast cancer.

We aimed to evaluate the effect of primary tumor resection on overall survival in stage IV breast cancer patients. In total, 284 breast cancer patients presenting with breast cancer at stage IV at initial diagnosis, between 2001 and 2014, were enrolled in the study. Patients were divided into two groups based on surgical resection of the primary tumor. Overall survival (OS) between the two groups was analyzed. Patients in the surgery group (n = 92) had smaller tumors than those in the no-surgery group (n = 192, T0-1:17.7% vs 34.8%, P < 0.001). The surgery group more often had negative nodal status (5.7% vs 33.7%, P < 0.001). Multiple metastatic organ sites were more common in the no-surgery group than in the surgery group (55.7% vs 15.2%, P < 0.001). The surgery group showed a better OS than the no-surgery group (P = 0.01). Multivariate analysis showed that surgical resection of primary tumors tended to be associated with improved OS (HR = 0.67, P = 0.055). T stage, ER, HER2 and metastatic organ sites were independent prognostic factors for OS in multivariate analysis. Surgical resection of the primary tumor may be a treatment option for patients with stage IV disease and may not have a negative effect on overall survival.

Impact of Micrometastatic Axillary Nodes on Survival of Breast Cancer Patients with Tumors ≤2 cm.

BACKGROUND: This study investigated the impact of pN1mi disease on the survival of T1 breast cancer patients and examined the clinical usefulness of the online PREDICT tool and updated staging system. METHODS: The node stages of 2344 patients were divided into pN0, pN1mi, and pN1a. Clinicopathological parameters and survival outcomes were retrospectively analyzed. Data for 111 micrometastatic diseases were applied to the PREDICT version 2.0 and re-classified using the 8th edition of the cancer staging manual. RESULTS: Univariable analyses demonstrated worse disease-free and overall survival rates for patients with node-positive cancer; however, the significance was not maintained in multivariable analyses. Chemotherapy improved outcomes in patients with node-positive and non-luminal A-like subtype cancers. The PREDICT tool demonstrated good performance when estimating the 5-year overall survival for pN1mi disease (area under the receiver operating characteristic curve, 0.834). According to the updated staging system, 74% of cases were down-staged to IA, and clearly splitting survival curves were identified. CONCLUSION: pN1mi disease alone did not adversely affect survival outcomes. Biologic and treatment factors determined outcomes in cases of small-volume node micrometastasis. The PREDICT tool or new staging classification could help predict the survival of patients with micrometastatic sentinel nodes.

Association between Changes in Serum 25-Hydroxyvitamin D Levels and Survival in Patients with Breast Cancer Receiving Neoadjuvant Chemotherapy.

PURPOSE: We investigated the changes in serum 25-hydroxyvitamin D (25[OH]D) levels before and after neoadjuvant chemotherapy (NCT) and the associations with pathologic complete response (pCR) and survival in patients with breast cancer. METHODS: Serum 25(OH)D concentrations were measured pre- and post-NCT in 374 patients between 2010 and 2013. Based on a cutoff of 20 ng/mL, patients were categorized into "either sufficient" or "both deficient" groups. The associations with clinicopathological data, including pCR and survival, were analyzed using multivariable analyses. RESULTS: Patients with either pre- or post-NCT sufficient 25(OH)D levels accounted for 23.8%, and the overall pCR rate was 25.9%. Most patients showed 25(OH)D deficiency at diagnosis and 65.8% showed decreased serum levels after NCT. Changes in 25(OH)D status were associated with postmenopause status, rural residence, baseline summer examination, and molecular phenotype, but not pCR. No association between survival and 25(OH)D status was found, including in the subgroup analyses based on molecular phenotypes. CONCLUSION: Most Korean patients with breast cancer showed vitamin D deficiency at diagnosis and a significant decrease in the serum concentration after NCT. No association with oncologic outcomes was found. Therefore, although optimal management for vitamin D deficiency is urgent for skeletal health, further research is warranted to clearly determine the prognostic role of vitamin D in patients with breast cancer who are candidates for NCT.

PEGylated TRAIL ameliorates experimental inflammatory arthritis by regulation of Th17 cells and regulatory T cells.

TNF-related apoptosis-inducing ligand (TRAIL) is a death ligand that can induce apoptosis in cells expressing its cognate death receptors (DRs). Previously, we demonstrated the therapeutic potential of recombinant human TRAIL in experimental rheumatoid arthritis (RA) models. However, the mechanisms of how DR-mediated apoptosis elicits these actions is not known. Here, we show that systemically administering a potent, long-acting PEGylated TRAIL (TRAILPEG) is profoundly anti-rheumatic against two complementary experimental RA mouse models, collagen-induced arthritis (CIA) and collagen antibody-induced arthritis (CAIA), via targeting IL-17 secreting Th17 cells and regulatory T cells (Treg). Systemic administration of TRAILPEG after disease onset ameliorated the severity of inflammatory arthritis including arthritis indices, paw thickness, cartilage damage and neutrophil infiltration in both CIA and CAIA models. Additionally, the levels of inflammatory molecules (p-p65, ICAM-1, Cox-2, MMP3, and iNOS), pro-inflammatory cytokines (TNF-α, IL-1ß, IFN-γ, IL-6, IL-17) and accumulation of activated macrophages were significantly reduced after the TRAILPEG treatment. Importantly, TRAILPEG decreased the number of pro-inflammatory Th17 cells in inflamed arthritic joints through TRAIL-induced apoptosis while increasing anti-inflammatory Treg population in vivo. These results suggest that TRAILPEG ameliorates autoimmunity by targeting the Th 17-Tregs axis, making it a promising candidate drug for the treatment of RA.

Preoperative prediction of the size of pure ductal carcinoma in situ using three imaging modalities as compared to histopathological size: does magnetic resonance imaging add value?

PURPOSE: The purpose of this study was to evaluate whether magnetic resonance imaging (MRI) and ultrasonography add value to traditional mammography in an Asian population with ductal carcinoma in situ (DCIS). METHODS: Data of 244 patients with pure DCIS treated at Severance Hospital between 2013 and 2015 were analyzed retrospectively. Data extracted included age, preoperative diagnosis, tumor size on preoperative imaging studies, and final histopathological tumor type and size, including hormone receptor status. The extent of correlation between imaging and histopathological tumor sizes was evaluated using a variety of methods, including Bland-Altman analysis. RESULTS: The mean patient age was 52.39 years (SD = 10.31). The mean measurements of the tumor on preoperative ultrasonography, mammography, MRI, and histopathology were 1.80 (SD = 1.23) cm, 2.97 (SD = 1.92) cm, 2.53(SD = 1.84) cm, and 1.88 (SD = 1.36) cm, respectively. The mean differences in tumor size between ultrasonography, mammography, and MRI compared with histopathology were -0.09 (SD = 1.39), 1.09 (SD = 1.89), and 0.65 (SD = 1.78), respectively. The correlation between the sizes was significant with r values for ultrasonography, mammography, and MRI of 0.447 (SE = 0.061), 0.375 (SE = 0.042), and 0.409 (SE = 0.043), respectively. Mammography and MRI estimated tumor size significantly better for patients older than 50 years (p = 0.045 and <0.001, respectively). Mammography also provided good estimation for patients with a body mass index under 25 (p = 0.041). CONCLUSION: MRI is better at estimation of histopathological DCIS size compared with mammography. However, ultrasonography had better estimation compared with MRI and mammography, probably owing to the high breast density in this population.

Resting heart rate as a prognostic factor for mortality in patients with breast cancer.

Although elevated resting heart rate (RHR) has been shown to be associated with mortality in the general population and patients with certain diseases, no study has examined this association in patients with breast cancer. A total of 4786 patients with stage I-III breast cancer were retrospectively selected from the Severance hospital breast cancer registry in Seoul, Korea. RHR was measured at baseline and the mean follow-up time for all patients was 5.0 ± 2.5 years. Hazard ratios (HRs) with 95 % confidence intervals (CIs) were calculated using Cox regression models. After adjustment for prognostic factors, patients in the highest quintile of RHR (≥85 beat per minute (bpm)) had a significantly higher risk of all-cause mortality (HR: 1.57; 95 %CI 1.05-2.35), breast cancer-specific mortality (HR: 1.69; 95 %CI 1.07-2.68), and cancer recurrence (HR: 1.49; 95 %CI 0.99-2.25), compared to those in the lowest quintile (≤67 bpm). Moreover, every 10 bpm increase in RHR was associated with 15, 22, and 6 % increased risk of all-cause mortality, breast cancer-specific mortality, and cancer recurrence, respectively. However, the association between RHR and cancer recurrence was not statistically significant (p = 0.26). Elevated RHR was associated with an increased risk of mortality in patients with breast cancer. The findings from this study suggest that RHR may be used as a prognostic factor for patients with breast cancer in clinical settings.

Exendins and exendin analogs for diabetic therapy: a patent review (2012-2015).

INTRODUCTION: Since exendin-4 (exenatide) was approved for diabetes therapy in 2005, several exendin analogs have been developed for the treatment of type 2 diabetes mellitus. As exenatide is a relatively short-acting injectable agent, major approaches have focused on developing long-acting exendin analogs to improve patient compliance and convenience. AREAS COVERED: In this review, the authors report on patents related to exendins and exendin analogs from 2012 to 2015. The patents have been divided into three categories based on the technologies used to develop the new chemical entities: 1) chemical bioconjugate analogs; 2) recombinant fusion protein analogs; and 3) multifunctional peptide analogs. EXPERT OPINION: Recently, research on exendins and their analogs has grown significantly, leading to the development of long-acting analogs and multifunctional peptides. While long-acting injectable agents are still the major products in the pharmaceutical industry, a significant growth is expected in the development of orally available exendins.

Expression of T-Lymphocyte Markers in Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer.

PURPOSE: The present study aimed to examine the clinical implications of CD4, CD8, and FOXP3 expression on the prognosis of human epidermal growth factor receptor 2 (HER2)-positive breast cancer using a web-based database, and to compare the immunohistochemical expression of T-lymphocyte markers using primary and metastatic HER2-positive tumor tissues before and after HER2-targeted therapy. METHODS: Using the cBioPortal for Cancer Genomics and Kaplan-Meier plotter, the mRNA expression, association between T-lymphocyte markers, and survival in HER2-positive cancers were investigated according to various cutoff levels. Immunohistochemistry analysis was performed using paired primary and metastatic tissues of 29 HER2-positive tumors treated with systemic chemotherapy and HER2-directed therapy. RESULTS: HER2 mRNA was mutually exclusive of T-lymphocyte markers, and a significant correlation between T-cell markers was observed in the cBioPortal for Cancer Genomics. According to analysis of the Kaplan-Meier plotter, the impact of T-lymphocyte marker expression on survival was statistically insignificant in clinical HER2-positive tumors, irrespective of the cutoff levels. However, in the intrinsic HER2-positive subtype, the individual analyses of T-cell markers except for FOXP3 and combined analysis showed significantly favorable survival irrespective of cutoff points. Although the small clinical sample size made it difficult to show the statistical relevance of immunohistochemistry findings, good responses to neoadjuvant treatments might be associated with positive expression of combined T-lymphocyte markers, and approximately half of the samples showed discordance of combined markers between baseline and resistant tumors. CONCLUSION: T-lymphocyte markers could be favorable prognostic factors in HER2-positive breast cancers; however, a consensus on patient section criteria, detection methods, and cutoff value could not be reached. The resistance to HER2-directed therapy might involve different and personalized mechanisms, and further research is required to understand the association between immune function and HER2 expression and to overcome the resistance mechanisms to HER2-targeted therapies.

Systemic PEGylated TRAIL treatment ameliorates liver cirrhosis in rats by eliminating activated hepatic stellate cells.

UNLABELLED: Liver fibrosis is a common outcome of chronic liver disease that leads to liver cirrhosis and hepatocellular carcinoma. No US Food and Drug Administration-approved targeted antifibrotic therapy exists. Activated hepatic stellate cells (aHSCs) are the major cell types responsible for liver fibrosis; therefore, eradication of aHSCs, while preserving quiescent HSCs and other normal cells, is a logical strategy to stop and/or reverse liver fibrogenesis/fibrosis. However, there are no effective approaches to specifically deplete aHSCs during fibrosis without systemic toxicity. aHSCs are associated with elevated expression of death receptors and become sensitive to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced cell death. Treatment with recombinant TRAIL could be a potential strategy to ameliorate liver fibrosis; however, the therapeutic application of recombinant TRAIL is halted due to its very short half-life. To overcome this problem, we previously generated PEGylated TRAIL (TRAILPEG ) that has a much longer half-life in rodents than native-type TRAIL. In this study, we demonstrate that intravenous TRAILPEG has a markedly extended half-life over native-type TRAIL in nonhuman primates and has no toxicity in primary human hepatocytes. Intravenous injection of TRAILPEG directly induces apoptosis of aHSCs in vivo and ameliorates carbon tetrachloride-induced fibrosis/cirrhosis in rats by simultaneously down-regulating multiple key fibrotic markers that are associated with aHSCs. CONCLUSION: TRAIL-based therapies could serve as new therapeutics for liver fibrosis/cirrhosis and possibly other fibrotic diseases. (Hepatology 2016;64:209-223).

Delivery of tumor-homing TRAIL sensitizer with long-acting TRAIL as a therapy for TRAIL-resistant tumors.

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) has attracted great interest as a cancer therapy because it selectively induces death receptor (DR)-mediated apoptosis in cancer cells while sparing normal tissue. However, recombinant human TRAIL demonstrates limited therapeutic efficacy in clinical trials, possibly due to TRAIL-resistance of primary cancers and its inherent short half-life. Here we introduce drug delivery approaches to maximize in vivo potency of TRAIL in TRAIL-resistant tumor xenografts by (1) extending the half-life of the ligand with PEGylated TRAIL (TRAILPEG) and (2) concentrating a TRAIL sensitizer, selected from in vitro screening, in tumors via tumor-homing nanoparticles. Antitumor efficacy of TRAILPEG with tumor-homing sensitizer was evaluated in HCT116 and HT-29 colon xenografts. Western blot, real-time PCR, immunohistochemistry and cell viability assays were employed to investigate mechanisms of action and antitumor efficacy of the combination. We discovered that doxorubicin (DOX) sensitizes TRAIL-resistant HT-29 colon cancer cells to TRAIL by upregulating mRNA expression of DR5 by 60% in vitro. Intravenously administered free DOX does not effectively upregulate DR5 in tumor tissues nor demonstrate synergy with TRAILPEG in HT-29 xenografts, but rather introduces significant systemic toxicity. Alternatively, when DOX was encapsulated in hyaluronic acid-based nanoparticles (HAC/DOX) and intravenously administered with TRAILPEG, DR-mediated apoptosis was potentiated in HT-29 tumors by upregulating DR5 protein expression by 70% and initiating both extrinsic and intrinsic apoptotic pathways with reduced systemic toxicity compared to HAC/DOX or free DOX combined with TRAILPEG (80% vs. 40% survival rate; 75% vs. 34% tumor growth inhibition). This study demonstrates a unique approach to overcome TRAIL-based therapy drawbacks using sequential administration of a tumor-homing TRAIL sensitizer and long-acting TRAILPEG.

Mono-lithocholated exendin-4-loaded glycol chitosan nanoparticles with prolonged antidiabetic effects.

Hydrophobically modified glycol chitosan (HGC) nanoparticles loaded with mono-lithocholic acid-conjugated exendin-4 at the Lys(27) residue (LAM1-Ex4) were prepared and characterized by particle size measurement, proteolytic stability, in vitro drug-release profile, and in vivo antidiabetic effects in a db/db diabetic mouse model. Compared with Ex-4-loaded HGC nanoparticles (Ex4/HGC NPs) prepared as a control, LAM1-Ex4-loaded HGC nanoparticles (LAM1-Ex4/HGC NPs) showed improved drug-loading efficiency, small particle size, enhanced resistance against proteolytic digestion, and an extended in vitro drug release profile. These findings may be attributable to the strong hydrophobic interaction between LAM1-Ex4 and the inner core of HGC. Furthermore, LAM1-Ex4/HGC NPs showed prolonged hypoglycemic efficacy in db/db mice, lasting 1 week after a single subcutaneous administration. The present study demonstrated that LAM1-Ex4/HGC NPs have considerable potential as a long-acting sustained-release antidiabetic system for type 2 diabetes.

Bioequivalence of a single 400-mg dose of imatinib 100-mg oral tablets and a 400-mg tablet in healthy adult Korean volunteers.

BACKGROUND: Imatinib mesylate (IM) is a selective tyrosine kinase inhibitor for the treatment of chronic myeloid leukemia and gastrointestinal stromal tumors. A new once-daily 400-mg film-coated tablet of imatinib has been developed by a pharmaceutical company in Korea. OBJECTIVE: The present study was designed to assess and compare the PK parameters, bioavailability, and bioequivalence of the new imatinib 400-mg formulation (test) versus the conventional 100-mg formulation (reference) administered as a single 400-mg dose in healthy adult male volunteers. METHODS: This randomized, open-label, single-dose, two-way crossover study was conducted in healthy Korean male volunteers. Eligible subjects were randomly assigned in a 1 : 1 ratio to receive 400 mg of the test (one 400-mg tablet) or reference (four 100-mg tablets) formulation, followed by a 2-week washout period and administration of the alternate formulation. Serial blood samples were collected at 0 (predose), 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 24, 48, and 72 hours after administration. Plasma imatinib concentrations were determined using liquid chromatography coupled with tandem mass spectrometry. The formulations were to be considered bioequivalent if the 90% confidence intervals (CIs) of the adjusted geometric mean ratios for Cmax, AUC(0-t), and AUC(0-∞)ž were within the predetermined range of 0.80 - 1.25. RESULTS: In total, 35 subjects completed the study. No serious adverse event was reported during the study. The 90% CIs of the adjusted geometric mean ratios of the test formulation to the reference formulation for C(max), AUC(0-t) and AUC(0-∞)ž of imatinib were all within the bioequivalence criteria range of 0.8 - 1.25. CONCLUSIONS: The test formulation of imatinib met the Korean regulatory requirements for bioequivalence. Both imatinib formulations were well-tolerated in all subjects.

Evaluation of PEGylated exendin-4 released from poly (lactic-co-glycolic acid) microspheres for antidiabetic therapy.

Peptide-based therapies have the potential to induce antibody formation if the molecules differ from a native human peptide. Several reports have disclosed the occurrence of antibody generation in a patient treated with exenatide. The immune response can be problematic from a clinical stand point, particularly if the antibodies neutralize the efficacy of the biotherapeutic agent or cause a general immune reaction. To overcome this limit, PEGylated exendin-4 analogs were designed and examined for metabolic stability and biological activity. To develop an extended release delivery system for exendin-4 for the safe and effective delivery of bioactive exendin-4 without peptide acylation and immunogenicity, PEGylated exendin-4 was encapsulated into poly (lactic-co-glycolic acid) (PLGA) microspheres by w/o/w double emulsion solvent evaporation method. Peptide-loaded microspheres were characterized in terms of morphology, particle diameter, and peptide encapsulation efficiency. Then, the release profile of the peptide from PLGA microspheres and the acylated products from PLGA polymer degradation was determined. The results obtained showed that the stability of exendin-4 was greatly improved by PEGylation. Moreover, eliminated acylation during PLGA polymer degradation in vitro and reduced immunogenicity in vivo were observed. The findings demonstrate that PEGylated exendin-4-loaded microspheres may be a safe and biocompatible system for clinical development.

Site-specific PEGylated Exendin-4 modified with a high molecular weight trimeric PEG reduces steric hindrance and increases type 2 antidiabetic therapeutic effects.

The purpose of this study was to optimize an Exendin-4 (Ex4-Cys) site-specific PEGylation method with a high-molecular-weight trimeric PEG. Here, we describe the preparation of C-terminal specific PEGylated Ex4-Cys (C40-tPEG-Ex4-Cys), which was performed using cysteine and amine residue specific coupling reactions between Ex4-Cys and activated trimeric PEG. The C40-PEG-Ex4-Cys was obtained at high yields (~83%) and characterized by MALDI-TOF mass spectrometry. The receptor binding affinity of C40-PEG(5K)-Ex4-Cys was 3.5-fold higher than that of N-terminal PEGylated Ex4-Cys (N(ter)-PEG(5K)-Ex4-Cys), and receptor binding by the trimeric PEG (tPEG; 23, 50 kDa) adduct was much higher than that of branched PEG (20 kDa). Furthermore, C40-tPEG(50K)-Ex4-Cys was found to have greater blood circulating t(1/2) and AUC(inf) values than native Ex4-Cys by 7.53- and 45.61-fold, respectively. Accordingly, its hypoglycemic duration was much greater at 59.2 h than that of native Ex4-Cys at 7.3 h, with a dose of 25 nM/kg. The results of this study show that C-terminal specific PEGylation using trimeric PEG is effective when applied to Ex4-Cys and suggest that C40-tPEG(50K)-Ex4-Cys has considerable potential as a type 2 antidiabetic agent.

Low molecular weight (1 kDa) polyethylene glycol conjugation markedly enhances the hypoglycemic effects of intranasally administered exendin-4 in type 2 diabetic db/db mice.

An intranasally active glucagon-like peptide-1 (GLP-1) formulation would have great advantages over conventional injectable therapies for the treatment of diabetic patients. The purpose of this study was to investigate the biological potentials of PEGylated exendin-4 (PEG-Ex4) analogs administered intranasally and the effects of polyethylene glycol (PEG) molecular weight (1, 2, 5 kDa) on nasal absorption. Initially, PEGEx4 analogs were site-specifically PEGylated to Lys²7-amine, and their bioactivities and stabilities were studied in vitro. The hypoglycemic effects and pharmacokinetics of these analogs after nasal administration were evaluated in type 2 diabetic animal models. PEG-Ex4 analogs had 3.1-, 3.8-, and 5.9-fold increased stabilities in rat nasal homogenates than Ex4. However, Lys²7-PEG(1k)-Ex4 was found to have well-preserved bioactivities (83.3% potency vs. Ex4), and other analogs were found to have much lower bioactivities than Lys²7-PEG(1k)-Ex4. In particular, the in vivo pharmacokinetic parameters of Lys²7-PEG(1k)-Ex4 in intranasally administered rats were significantly improved by PEGylation. Area under the curve (AUC) values of Lys²7-PEG(1k)-Ex4 were 33.6-fold higher and circulating t(1/2) values was 27.1-fold higher than Ex4. But, other analogs were not effectively absorbed via the intranasal route, because the higher molecular weight PEG (over 2 kDa) limited intranasal absorption. Finally, in vivo hypoglycemic experiment showed that Lys²7-PEG(2k)-, Lys²7-PEG(5k)-Ex4 had significantly lower hypoglycemic efficacies than Lys²7-PEG(1k)-Ex4, probably because of their lower intrinsic bioactivities and intranasal absorptions. Taken together, our findings suggest that the site-specific conjugation of appropriately sized PEG (1 kDa) substitution onto peptides like Ex4 offers two advantages for deliveryvia the intranasal route, namely, increased stability and extended circulating half-life.

PEG-transferrin conjugated TRAIL (TNF-related apoptosis-inducing ligand) for therapeutic tumor targeting.

Transferrin (Tf) is considered an effective tumor-targeting agent, and PEGylation effectively prolongs in vivo pharmacokinetics by delaying excretion via the renal route. The authors describe the active tumor targeting of long-acting Tf-PEG-TNF-related apoptosis-inducing ligand conjugate (Tf-PEG-TRAIL) for effective cancer therapy. Tf-PEG-TRAIL was prepared using a two-step N-terminal specific PEGylation procedure using different PEGs (Mw: 3.4, 5, 10 kDa). Eventually, only 10 kDa PEG was linked to Tf and TRAIL because TRAIL (66 kDa) and Tf (81 kDa) were too large to link to 3.4 and 5 kDa PEG. The final conjugate Tf-PEG(10K)-TRAIL was successfully purified and characterized by SDS-PAGE, western blotting. To determine the specific binding of Tf-PEG(10K)-TRAIL to Tf receptor, competitive receptor binding assays were performed on K 562 cells. The results obtained demonstrate that the affinity of Tf-PEG(10K)-TRAIL for Tf receptor is similar to that of native Tf. In contrast, PEG(10K)-TRAIL demonstrated no specificity. Biodistribution patterns and antitumor effects were investigated in C57BL6 mice bearing B16F10 murine melanomas and BALB/c athymic mice bearing HCT116. Tumor accumulation of Tf-PEG(10K)-TRAIL was 5.2 fold higher (at 2 h) than TRAIL, because Tf-PEG(10K)-TRAIL has both passive and active tumor targeting ability. Furthermore, the suppression of tumors by Tf-PEG(10K)-TRAIL was 3.6 and 1.5 fold those of TRAIL and PEG(10K)-TRAIL, respectively. These results suggest that Tf-PEG(10K)-TRAIL is a superior pharmacokinetic conjugate that potently targets tumors and that it should be viewed as a potential cancer therapy.

Improved biological half-life and anti-tumor activity of TNF-related apoptosis-inducing ligand (TRAIL) using PEG-exposed nanoparticles.

TRAIL has received considerable attention as a potential anti-cancer agent due to its specific ability to target tumors. However, recombinant TRAIL has several limitations, such as, its short biological half-life, its inherent instability, and its potential hepatotoxicity. In this study, we developed a sustained release nanoparticle formulation of TRAIL and investigated its therapeutic effects in tumor-bearing mice. TRAIL-loaded nanoparticles (NPs) were prepared by mixing PEGylated heparin (PEG-HE), poly-L-lysine (PLL), and TRAIL. NPs prepared by the ionic interaction between polymer and TRAIL showed uniform spherical structures of diameter 213.3 ± 9.7 nm and a surface charge of 5.33 ± 1.2 mV. An in vitro study of the bioactivity of TRAIL in NPs showed that TRAIL-loaded PEG-HE/PLL NPs (TRAIL-PEG-NPs) were slightly less cytotoxic than TRAIL in vitro. To investigate pharmacokinetic parameters, TRAIL and TRAIL-PEG-NPs were intravenously injected into SD rats. The PEG-NP-based formulation demonstrated a 28.3 fold greater half-life than TRAIL alone. To evaluate the anti-tumor effect, TRAIL, TRAIL-loaded HE/PLL NPs (TRAIL-NPs), and TRAIL-PEG-NPs were intravenously injected into HCT-116 tumor-bearing BALB/c athymic mice. The TRAIL-PEG-NP formulation efficiently suppressed tumor growth (>70%), and histological findings confirmed that NPs induced significant tumor cell apoptosis without inducing liver toxicity. The PEG-exposed NP fabrication method applied in this study could be widely applied to protein and peptide delivery systems.