PDE3B regulates KRT6B and increases the sensitivity of bladder cancer cells to copper ionophores.

Cuproptosis is a new Cu-dependent programmed cell death manner that has shown regulatory functions in many tumor types, however, its mechanism in bladder cancer remains unclear. Here, we reveal that Phosphodiesterase 3B (PDE3B), a cuproptosis-associated gene, could reduce the invasion and migration of bladder cancer. PDE3B is downregulated in bladder cancer tissues, which is correlated with better prognosis. Conversely, overexpression of PDE3B in bladder cancer cell could significantly resist invasion and migration, which is consistent with the TCGA database results. Future study demonstrate the anti-cancer effect of PDE3B is mediated by Keratin 6B (KRT6B) which leads to the keratinization. Therefore, PDE3B can reduce KRT6B expression and inhibit the invasion and migration of bladder cancer. Meanwhile, increased expression of PDE3B was able to enhance the sensitivity of Cuproptosis drug thiram. This study show that PDE3B/KRT6B is a potential cancer therapeutic target and PDE3B activation is able to increase the sensitivity of bladder cancer cells to copper ionophores.

Exosomal biomarkers in the differential diagnosis of ovarian tumors: the emerging roles of CA125, HE4, and C5a.

OBJECTIVE: Investigating the utility of serum exosomal markers CA125, HE4, and C5a, both individually and in combination, for distinguishing between benign and malignant ovarian tumors. METHODS: In this study, we selected a total of 234 patients diagnosed with ovarian tumors, including 34 with malignant tumors, 10 with borderline ovarian tumors, and 190 with benign tumors. This study conducted comparisons of exosomal levels of CA125, HE4, and C5a among distinct groups, as well as making comparisons between serum and exosomal levels of CA125 and HE4. Furthermore, the diagnostic performance was assessed through Receiver Operating Characteristic (ROC) curve analysis. The Area Under the Curve (AUC) was computed, and a comparative evaluation of sensitivity and specificity was conducted to ascertain their effectiveness in determining the nature of ovarian tumors across different markers. RESULTS: Serum CA125 and HE4 levels, the ROMA index, exosomal CA125, HE4, C5a levels, and their combined applied value (OCS value) were notably elevated in the ovarian non-benign tumor group compared to the benign tumor group, with statistical significance (P < 0.05). Exosomal and serum levels of CA125 and HE4 exhibited a positive correlation, with concentrations of these markers in serum surpassing those in exosomes. The combined OCS (AUC = 0.871) for CA125, HE4, and C5a in exosomes demonstrated superior sensitivity (0.773) and specificity (0.932) compared to serum tumor markers (CA125, HE4) and the ROMA index. The tumor stage represents an autonomous risk factor influencing the prognosis of individuals with ovarian malignancies. CONCLUSION: The stage of ovarian malignancy is an independent risk factor for its prognosis. The combination of exosomal CA125, HE4 and C5a has a higher clinical value for the identification of the nature of ovarian tumours.

Artificial intelligence in endoscopic ultrasonography: risk stratification of gastric gastrointestinal stromal tumors.

Background: Previous studies have identified useful endoscopic ultrasonography (EUS) features to predict the malignant potential of gastrointestinal stromal tumors (GISTs). However, the results of the studies were not consistent. Artificial intelligence (AI) has shown promising results in medicine. Objectives: We aimed to build a risk stratification EUS-AI model to predict the malignancy potential of GISTs. Design: This was a retrospective study with external validation. Methods: We developed two models using EUS images from two hospitals to predict the GIST risk category. Model 1 was the four-category risk EUS-AI model, and Model 2 was the two-category risk EUS-AI model. The diagnostic performance of the models was validated with external cohorts. Results: A total of 1320 images (880 were very low-risk, 269 were low-risk, 68 were intermediate-risk, and 103 were high-risk) were finally chosen for building the models and test sets, and a total of 656 images (211 were very low-risk, 266 were low-risk, 88 were intermediate-risk, and 91 were high-risk) were chosen for external validation. The overall accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the four-category risk EUS-AI model in the external validation sets by tumor were 74.50%, 55.00%, 79.05%, 53.49%, and 81.63%, respectively. The accuracy, sensitivity, specificity, PPV, and NPV for the two-category risk EUS-AI model for the prediction of very low-risk GISTs in the external validation sets by tumor were 86.25%, 94.44%, 79.55%, 79.07%, and 94.59%, respectively. Conclusion: We developed a EUS-AI model for the risk stratification of GISTs with promising results, which may complement current clinical practice in the management of GISTs. Registration: The study has been registered in the Chinese Clinical Trial Registry (No. ChiCTR2100051191).

Evaluation of three scoring systems for predicting renal prognosis in antineutrophil cytoplasmic antibody-associated glomerulonephritis.

BACKGROUND: Antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (AAGN) is characterized by rapidly progressive glomerulonephritis, and timely initiation of treatment and evaluation is critical to prevent the progression of renal disease to end-stage renal disease (ESRD). The aim of this study was to evaluate predictive value of the renal risk score (RRS), Birmingham vasculitis activity score (BVAS), and renal vascular lesions (RVLs) score for renal prognosis in AAGN. METHODS: A retrospective analysis of ninety-four patients diagnosed with AAGN after renal biopsy was performed. The RRS, BVAS, and RVLs score were evaluated in relation to clinicopathologic features and renal prognosis. A receiver operating characteristic curve (ROC) was used to evaluate their renal prognostic value. RESULTS: The median follow-up time was 36 months. Thirty-eight patients progressed to ESRD. Survival analysis showed that renal prognosis worsened in the RRS group in order of low, medium, and high RRS (P < 0.05). Within the RVLs group, the renal prognosis of the groups with severe and moderate RVLs was worse than that of the group without RVLs (P = 0.012, P < 0.001), and the group with mild RVLs was close to that of the group without RVLs. ROC analysis showed that the AUC of RRS, BVAS, RVLs score, RVLs score combined with RRS (RVLs score & RRS, RR), RVLs score, and RRS combined with BVAS (RVLs score & RRS & BVAS, RRB) were 0.865, 0.624, 0.763, 0.910, and 0.942, respectively. The predictive power of RRB and RR was comparable and significantly better than the RRS, BVAS, and RVLs score. Based on simplicity and validity, RR was selected as the best predictor, and the relationship between RRS, RVLs score, and RR was calculated using a linear fit, resulting in the linear equation RR = -0.4766 + 0.1231 × RVLs score + 0.395 × RRS (P < 0.001). CONCLUSIONS: In AAGN, the predictive power of RR for renal prognosis was superior to that of RRS, BVAS, and RVLs score. RR may serve as a new predictor of renal prognosis in AAGN.

Artificial Intelligence in the Prediction of Gastrointestinal Stromal Tumors on Endoscopic Ultrasonography Images: Development, Validation and Comparison with Endosonographers.

Background/Aims: The accuracy of endosonographers in diagnosing gastric subepithelial lesions (SELs) using endoscopic ultrasonography (EUS) is influenced by experience and subjectivity. Artificial intelligence (AI) has achieved remarkable development in this field. This study aimed to develop an AI-based EUS diagnostic model for the diagnosis of SELs, and evaluated its efficacy with external validation. Methods: We developed the EUS-AI model with ResNeSt50 using EUS images from two hospitals to predict the histopathology of the gastric SELs originating from muscularis propria. The diagnostic performance of the model was also validated using EUS images obtained from four other hospitals. Results: A total of 2,057 images from 367 patients (375 SELs) were chosen to build the models, and 914 images from 106 patients (108 SELs) were chosen for external validation. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the model for differentiating gastrointestinal stromal tumors (GISTs) and non-GISTs in the external validation sets by images were 82.01%, 68.22%, 86.77%, 59.86%, and 78.12%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in the external validation set by tumors were 83.75%, 71.43%, 89.33%, 60.61%, and 80.56%, respectively. The EUS-AI model showed better performance (especially specificity) than some endosonographers. The model helped improve the sensitivity, specificity, and accuracy of certain endosonographers. Conclusions: We developed an EUS-AI model to classify gastric SELs originating from muscularis propria into GISTs and non-GISTs with good accuracy. The model may help improve the diagnostic performance of endosonographers. Further work is required to develop a multi-modal EUS-AI system.

Ratiometric electrochemiluminescence lab-on-paper device for DNA methylation determination based on highly conductive copper paper electrode.

Herein, a ratiometric electrochemiluminescence (ECL) lab-on-paper platform, based on enhancing effect of the N-(4-aminobutyl)-N-ethylisoluminol-functionalized glutathione-coated cobalt/gold bimetallic nanoclusters (GCAL) and quenching effect of carbon quantum dots (CQDs), as well as benefiting from high conductivity copper paper electrode, was developed to achieve accurate and sensitive analysis of DNA methylation. Concretely, due to one-to-multiple amplification effect, one target DNA could initiate the formation of supersandwich structure with multiple signal probes labeled with GCAL. Thus, the GCAL signal enhancement effect was realized. Simultaneously, multiple signal probes are connected to hinder the electron conduction rate on the electrode surface, which results in the quenching of CQDs signal. With the method proposed here, wide linear relationship in the range of 1 fM to 10 pM with a low detection limit of 0.27 fM for sensitive detecting methylated DNA was achieved. It is believed that this work provided a rapid, low-cost and stabilized method for specific determination of methylated DNA, and the immediate detection of cancer in the clinic will become possible in the future.

Comparison between endoscopic mucosal resection with a cap and endoscopic submucosal dissection for rectal neuroendocrine tumors.

BACKGROUND: The aim of this study is to evaluate and compare the safety and efficacy of endoscopic mucosal resection with a cap (EMR-c) with those of endoscopic submucosal dissection (ESD) for rectal neuroendocrine tumors (R-NETs) ≤ 15 mm in diameter, and to analyze the risk factors of incomplete resection. METHODS: A total of 122 patients who underwent EMR-c or ESD for R-NETs at the Fourth Hospital of Hebei Medical University between February 2007 and December 2020 were invovled in this study. The clinical outcomes of two groups were compared and evaluated. RESULTS: A total of 122 patients with 128 R-NETs underwent endoscopic resection (EMR-c, 80; ESD, 48). In terms of duration of operation, EMR-c was significantly shorter than ESD (p < 0.001). Univariate analysis and multivariate analysis suggested that tumor diameter ≥ 8 mm was an independent risk factor for incomplete resection in patients with R-NETs in this study. CONCLUSIONS: Both EMR-c and ESD were safe and effective treatments for R-NETs ≤ 15 mm in diameter. In addition, tumor diameter ≥ 8 mm was an independent risk factor for incomplete resection.

Programmed co-delivery of platinum nanodrugs and gemcitabine by a clustered nanocarrier for precision chemotherapy for NSCLC tumors.

Recently, ultra-small platinum nanoparticles (USPtNs) have been found that can kill cancer cells by leaching Pt ions into acidic organelles, such as cell endosomes or lysosomes. Unfortunately, tumor-specific accumulation is difficult to achieve with such platinum nanodrugs of less than 5 nm due to their short half-life in vivo and broad range of toxicity to normal tissues. Programmable multi-drug release for combinational chemotherapy by hierarchical nanostructures provides a promising solution for cancer-targeted therapy. Herein, we demonstrated a pH/redox dual stimuli-responsive clustered nanoparticle as a vehicle for simultaneously delivering USPtNs and gemcitabine (GEM) to treat non-small-cell lung cancer. The clustered nanoparticle (denoted as GP-NA) was composed of disulfide-bond-containing GEM-grafted copolymers (PEG-b-P(LL-g-GEM)), pH-sensitive polypeptides (OAPI), and USPtNs. Such a hybrid nanosystem completes multiple tasks inside cancer cells, which include the generation of cytotoxic Pt ions in response to lysosomal acidic environments and the subsequent release of GEM in cytoplasmic reduction environments. Compared with non-acid-sensitive nanoparticles or free drugs, GP-NA exhibited cumulative and enhanced anti-tumor efficacy in vivo, which may be attributed to the simultaneous inhibition of ribonucleotide reductase and DNA replication in nuclei by the GEM and Pt ions. Together, our work provides a promising strategy in the co-delivery of USPtNs and GEM for precision cancer chemotherapy.

Self-Healable, Fast Responsive Poly(ω-Pentadecalactone) Thermogelling System for Effective Liver Cancer Therapy.

A polyurethane based thermogelling system comprising poly(ω-pentadecalactone) (PPDL), poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG), termed as PDEP, was synthesized. The incorporation of PPDL lowers critical micelle concentration (CMC) as well as critical gelation concentration (CGC) of the novel copolymers compared to commercial Pluronic® F127. The thermogels showed excellent thermal stability at high temperature up to 80°C, fast response to temperature change in a time frame of less than second, as well as remarkable self-healing properties after being broken at high strain. In vitro drug release studies using docetaxel (DTX) and cell uptake studies using doxorubicin (DOX) show high potential of the hydrogel as drug reservoir for sustainable release profile of payloads, while the in vivo anti-tumor evaluation using mice model of hepatocellular carcinoma further demonstrated the significant inhibition on the growth of tumor. Together with its excellent biocompatibility in different organs, the novel PDPE thermogelling copolymers reported in this work could potentially be utilized as in situ-forming hydrogels for liver cancer therapy.

Wide-Spectrum-Responsive Paper-Supported Photoelectrochemical Sensing Platform Based on Black Phosphorus-Sensitized TiO2.

A wide-spectrum-responsive paper-based photoelectrochemical (PEC) sensor based on black phosphorus (BP) quantum dots (QDs)-sensitized titanium dioxide (TiO2-BP QDs) for prostate-specific antigen (PSA) detection was presented herein. Carbon nanotubes (CNTs) were first coated on paper to form a flexible conductive paper electrode. TiO2 nanoparticles were then in situ synthesized on the CNTs-modified paper working electrode with direct liquid-phase hydrolysis with normal temperature, shirtsleeve operation, and gentle solution. Meanwhile, BP QDs, derived from two-dimensional BP nanosheets, can harvest light from the ultraviolet to near-infrared region, broaden efficient utilization of light, add a new dimension to BP research, and impel the high expectation on the potentials of QDs. To implement an assay protocol, exciton-plasmon interactions between TiO2-BP QDs and gold nanoparticles were introduced into the PEC sensing platform for high sensitivity detection of the PSA antigen. Under the optimal conditions, this proposed method exhibited a linear response ranging from 0.005 to 50 ng/mL with a detection limit of 1 pg/mL. This sensing protocol offered a promising analytical method with favorable properties of high selectivity, stability, and reproducibility.

H7K(R2)2-modified pH-sensitive self-assembled nanoparticles delivering small interfering RNA targeting hepatoma-derived growth factor for malignant glioma treatment.

The lack of effective glioma therapeutics mandates the development of novel treatment strategies. Hepatoma-derived growth factor (HDGF) has been considered as a potential glioma therapeutic target, and its expression level in gliomas is positively related to the malignant grade. Although there are no effective and specific inhibitors against this target, small interfering RNA targeting HDGF (siHDGF)-mediated RNA interference (RNAi) can inhibit the target protein function by knockdown of HDGF expression. However, the application of siHDGF in glioma research and therapy is hampered by the challenge to safe and effective in vivo systemic delivery of siHDGF to gliomas. To address this question, we develop the peptide H7K(R2)2-modified pH-sensitive self-assembled hybrid nanoparticles encapsulating siHDGF (H7K(R2)2-PSNPs (siHDGF)). The acidic glioma microenvironment is beneficial to the membrane penetration of H7K(R2)2-PSNPs and the encapsulated siHDGF. Following systemic administration, H7K(R2)2-PSNPs (siHDGF) can effectively deliver siHDGF into the brain and malignant glioma cells, and therefore can significantly downregulate HDGF expression, inhibit malignant phenotypes of glioma cells, result in reduced tumor volumes and prolonged survival times in nude mice bearing U251 human glioblastoma. Thus, systemic administration of H7K(R2)2-PSNPs (siHDGF) offers an effective way for the targeted delivery of siHDGF and may serve as a practical malignant glioma therapy.

Bortezomib-catechol conjugated prodrug micelles: combining bone targeting and aryl boronate-based pH-responsive drug release for cancer bone-metastasis therapy.

The treatment of metastatic tumors is highly desirable in clinics, which has also increased the interest in the design of nanoscale drug delivery systems. Bone metastasis is one of the most common pathways in the metastasis of breast cancer, and it is also an important cause for tumor recurrence and death. The aryl boronate group, as an acid-labile linker, has been introduced into nano-assemblies in recent years. Especially, as a proteasome inhibitor anticancer drug with a boric acid group, bortezomib can facilitate the formation of pH-sensitive aryl boric acid ester linkage with the catecholic group. In this study, bortezomib-loaded micelles with bone targeting properties were constructed for the treatment of breast cancer bone metastasis. The mixed micelles employed alendronate (ALN) as the bone-targeting ligand and encapsulated bortezomib-catechol conjugates as the cargo. In vitro and in vivo studies showed that compared with free drugs or control micelles, these prodrug micelles (ALN-NP) exhibited many favorable properties such as reduced systemic toxicity and improved therapeutic effects. Therefore, ALN-NP is promising as a nanovehicle for bone-targeting delivery of chemotherapeutic drugs. Furthermore, this study offers a novel strategy combining bone targeting and aryl boronate-based pH-responsive drug release for anti-metastasis therapy.

Size shrinkable drug delivery nanosystems and priming the tumor microenvironment for deep intratumoral penetration of nanoparticles.

The penetration of nanomedicine into solid tumor still constitutes a great challenge for cancer therapy, which lead to the failure of thorough clearance of tumor cells. Aiming at solving this issue, lots of encouraging progress has been made in the development of multistage nanoparticles triggered by various stimuli in the past few years. Besides, the therapeutical effects of nanoagents are also greatly impacted by the complex tumor microenvironment, and remodeling tumor microenvironment has become another important approach for promoting nanoparticles penetration. In this review, we summarize and analyze recent research progress and challenges in promoting nanoparticle penetration based on two kinds of different strategies, which include size shrinkable nanoparticles and priming tumor microenvironments. Especially, many recent reported multi-strategy approaches based on particle size reduction in conjugated with other therapeutic strategies are discussed. And we expect to provide some useful enlightenments and proposals on nanotechnology-based drug delivery systems for more effective therapy of solid tumors.

pH-triggered surface charge-switchable polymer micelles for the co-delivery of paclitaxel/disulfiram and overcoming multidrug resistance in cancer.

Multidrug resistance (MDR) remains a major challenge for providing effective chemotherapy for many cancer patients. To address this issue, we report an intelligent polymer-based drug co-delivery system which could enhance and accelerate cellular uptake and reverse MDR. The nanodrug delivery systems were constructed by encapsulating disulfiram (DSF), a P-glyco-protein (P-gp) inhibitor, into the hydrophobic core of poly(ethylene glycol)-block-poly(l-lysine) (PEG-b-PLL) block copolymer micelles, as well as 2,3-dimethylmaleic anhydride (DMA) and paclitaxel (PTX) were grafted on the side chain of l-lysine simultaneously. The surface charge of the drug-loaded micelles represents as negative in plasma (pH 7.4), which is helpful to prolong the circulation time, and in a weak acid environment of tumor tissue (pH 6.5-6.8) it can be reversed to positive, which is in favor of their entering into the cancer cells. In addition, the carrier could release DSF and PTX successively inside cells. The results of in vitro studies show that, compared to the control group, the DSF and PTX co-loaded micelles with charge reversal exhibits more effective cellular uptake and significantly increased cytotoxicity of PTX to MCF-7/ADR cells which may be due to the inhibitory effect of DSF on the efflux function of P-gp. Accordingly, such a smart pH-sensitive nanosystem, in our opinion, possesses significant potential to achieve combinational drug delivery and overcome drug resistance in cancer therapy.

Thermo-responsive mesoporous silica/lipid bilayer hybrid nanoparticles for doxorubicin on-demand delivery and reduced premature release.

Hybrid nanocarriers based on mesoporous silica nanoparticles (MSNs) and supported lipid bilayer (SLB) have been studied as drug delivery system. It still remains challenges to develop these nanocarriers (SLB-MSNs) with on-demand drug release profile for chemotherapy. Here, we reported the biocompatible SLB-MSNs with high drug loading, which could release doxorubicin (DOX) in response to hyperthermia and reduce premature release. After synthesis of MSNs via a sol-gel procedure, the thermo-responsive SLB was deposited on the MSNs by sonication to completely seal the mesopores. The obtained SLB-MSNs consisted of 50 nm-sized MSN cores and 6.3 nm-thick SLB shells. Due to the big surface and pore volume of MSNs, the high drug loading content (7.30±0.02%) and encapsulation efficiency (91.16±0.28%) were achieved. The SLB blocking the mesopores reduced 50% of premature release and achieved on-demand release in a thermo-responsive manner. Moreover, SLB-MSNs showed good hemocompatibility at any tested concentration (25-700µg/mL), while bare MSNs caused 100% of hemolysis at concentration larger than 325µg/mL. In addition, in vitro U251 cell uptake experiment demonstrated that compared with uncapped MSNs, SLB-MSNs could prevent untargeted cellular uptake of DOX owing to reduced premature release and steric hindrance of PEG, which would be beneficial to minimize toxicity for healthy tissues. These results indicated that SLB-MSNs with thermo-responsive release capacity possessed great potential in future synergistic thermo-chemotherapy.

Enhanced Antiglioblastoma Efficacy of Neovasculature and Glioma Cells Dual Targeted Nanoparticles.

Combining treatment of anticancer cells and antiangiogenesis is considered to be a potential targeted strategy for brain glioblastoma therapy. In this study, by utilizing the overexpression of Interleukin 13 receptor α2 (IL-13Rα2) on the glioma cells and heparan sulfate on neovascular endothelial cells, we developed a paclitaxel (PTX) loaded Pep-1 and CGKRK peptide-modified PEG-PLGA nanoparticle (PC-NP-PTX) for glioma cells and neovasculature dual-targeted chemotherapy to enhance the antiglioma efficacy. There were significant differences both on the enhancement of cellular uptake in HUVEC and C6 cells and on the improvement of in vitro antiglioma activity in the respect of proliferation, tumor spheroid growth, tube formation, and migration between PC-NP-PTX and Taxol and NP-PTX. As for C6 cells, the IC50 were 3.59 ± 0.056, 2.37 ± 0.044, 1.38 ± 0.028, 1.82 ± 0.035, and 1.00 ± 0.016 µg/mL of Taxol, NP-PTX, Pep-NP-PTX, CGKRK-NP-PTX, and PC-NP-PTX, and for HUVEC cells, the IC50 were 0.44 ± 0.006, 0.33 ± 0.005, 0.25 ± 0.005, 0.19 ± 0.004, and 0.16 ± 0.004 µg/mL of Taxol, NP-PTX, Pep-NP-PTX, CGKRK-NP-PTX, and PC-NP-PTX, respectively. In vivo distribution assays confirmed that PC-NP-PTX targeted and accumulated effectively at glioma site. PC-NP-PTX showed a longer median survival time of 61 days when compared with Taxol (22 days), NP-PTX (24 days), Pep-NP-PTX (32 days), and CGKRK-NP-PTX (34 days). The in vivo antiglioma efficacy and safety evaluation showed PC-NP-PTX significantly enhanced the antiglioma efficacy and displayed negligible acute toxicity.

PEGylated Polyamidoamine dendrimer conjugated with tumor homing peptide as a potential targeted delivery system for glioma.

Glioblastoma multiforme (GBM) is the most common and aggressive primary central nervous system (CNS) tumor with a short survival time. The failure of chemotherapy is ascribed to the low transport of chemotherapeutics across the Blood Brain Tumor Barrier (BBTB) and poor penetration into tumor tissue. In order to overcome the two barriers, small nanoparticles with active targeted capability are urgently needed for GBM drug delivery. In this study, we proposed PEGylated Polyamidoamine (PAMAM) dendrimer nanoparticles conjugated with glioma homing peptides (Pep-1) as potential glioma targeting delivery system (Pep-PEG-PAMAM), where PEGylated PAMAM dendrimer nanoparticle was utilized as carrier due to its small size and perfect penetration into tumor and Pep-1 was used to overcome BBTB via interleukin 13 receptor α2 (IL-13Rα2) mediated endocytosis. The preliminary availability and safety of Pep-PEG-PAMAM as a nanocarrier for glioma was evaluated. In vitro results indicated that a significantly higher amount of Pep-PEG-PAMAM was endocytosed by U87 MG cells. In vivo fluorescence imaging of U87MG tumor-bearing mice confirmed that the fluorescence intensity at glioma site of targeted group was 2.02 folds higher than that of untargeted group (**p<0.01), and glioma distribution experiment further revealed that Pep-PEG-PAMAM exhibited a significantly enhanced accumulation and improved penetration at tumor site. In conclusion, Pep-1 modified PAMAM was a promising nanocarrier for targeted delivery of brain glioma.

Chronic dDAVP infusion in rats decreases the expression of P2Y2 receptor in inner medulla and P2Y2 receptor-mediated PGE2 release by IMCD.

Activation of P2Y2 receptor (P2Y2-R) in inner medullary collecting duct (IMCD) of rat decreases AVP-induced water flow and releases PGE(2). We observed that dehydration of rats decreases the expression of P2Y2 receptor in inner medulla (IM) and P2Y2-R-mediated PGE(2) release by IMCD. Because circulating vasopressin (AVP) levels are increased in dehydrated condition, we examined whether chronic infusion of desmopressin (dDAVP) has a similar effect on the expression and activity of P2Y2-R. Groups of rats were infused with saline or dDAVP (5 or 20 ng/h sc, 5 or 6 days) via osmotic minipumps and euthanized. Urine volume, osmolality, and PGE(2) metabolite content were determined. AQP2- and P2Y2- and V2-R mRNA and/or protein in IM were quantified by real-time RT-PCR and immunoblotting, respectively. P2Y2-R-mediated PGE(2) release by freshly prepared IMCD was assayed using ATPgammaS as a ligand. Chronic dDAVP infusion resulted in low-output of concentrated urine and significantly increased the AQP2 protein abundance in IM. On the contrary, dDAVP infusion at 5 or 20 ng/h significantly decreased P2Y2-R protein abundance (approximately 40% of saline-treated group). In parallel, the relative expression of P2Y2-R vs. AQP2- or V2-R mRNA was significantly decreased. Furthermore, the P2Y2-R-mediated PGE(2) release by IMCD was significantly decreased in rats infused 20 ng/h but not 5 ng/h of dDAVP. Urinary PGE(2) metabolite excretion, however, did not change with dDAVP infusion. In conclusion, chronic dDAVP infusion decreases the expression and activity of P2Y2-R in IM. This may be due to a direct effect of dDAVP or dDAVP-induced increase in medullary tonicity.

Expression of NTPDase1 and NTPDase2 in murine kidney: relevance to regulation of P2 receptor signaling.

The regulation of renal function by extracellular nucleotides encompasses alterations in glomerular hemodynamics, microvascular function, tubuloglomerular feedback, tubular transport, cell growth or apoptosis, and transport of water and solutes in the medullary collecting duct. Nearly all cells can release ATP or other nucleotides that are then rapidly hydrolyzed in the extracellular milieu. However, little information is available on the cellular expression of ectoenzymes that hydrolyze extracellular nucleotides within the kidney. Nucleoside triphosphate diphosphohydrolases (NTPDases) are plasma membrane-bound ectonucleotidases. NTPDase1 has identity with CD39, a B lymphocyte activation marker, and hydrolyzes extracellular ATP and ADP to AMP within the vasculature, whereas NTPDase2/CD39L(ike)1 preferentially converts ATP to ADP outside of blood vessels. Using immunohistochemical and in situ hybridization approaches, we localized the protein and mRNA of NTPDase1 and 2 in murine renal tissues. In the renal cortex, NTPDase1 is expressed by vascular smooth muscle cells and endothelium in interlobular arteries, afferent glomerular arterioles, and peritubular capillaries. In the inner medulla, NTPDase1 is expressed in ascending thin limbs of Henle's loop, ducts of Bellini, and in the pelvic wall. In contrast, NTPDase2 is expressed in Bowman's capsule, glomerular arterioles, adventitia of blood vessels, and pelvic wall. Thus the distribution patterns of NTPDases have parallels to the known distribution of P2 receptors within the kidney. NTPDases may modulate regulatory effects of ATP and degradation products within the vasculature and other sites and thereby potentially influence physiological as well as multiple pathological events in the kidney.

P2Y2 receptor-stimulated release of prostaglandin E2 by rat inner medullary collecting duct preparations.

Extracellular nucleotides, acting through the P2Y2 receptor and the associated phosphoinositide-Ca2+ signaling pathway, inhibit AVP-stimulated osmotic water permeability in rat inner medullary collecting duct (IMCD). Because a rise in intracellular Ca2+ is frequently associated with enhanced arachidonic acid metabolism, we examined the effect of activation of the P2Y2 receptor on release of PGE2 in freshly prepared rat IMCD suspensions. Unstimulated IMCD released moderate, but significant, amounts of PGE2, which were more sensitive to cyclooxygenase (COX)-2 than COX-1 inhibition. Agonist activation of P2Y2 receptor by adenosine 5'-O-(3-thiotriphosphate) enhanced release of PGE2 from IMCD in a time- and concentration-dependent fashion. Purinergic-stimulated release of PGE2 was completely blocked by nonspecific COX inhibitors (flurbiprofen and 2-acetoxyphenylhept-2-ynyl sulfide). Differential COX inhibition studies revealed that purinergic-stimulated release of PGE2 was more sensitive to a COX-1-specific inhibitor (valeroyl salicylate) than a COX-2-specific inhibitor (NS-398). Thus purinergic stimulation resulted in significantly more release of PGE2 in the presence of COX-2 inhibitor than COX-1 inhibitor. If it is assumed that increased release of PGE2 is related to its increased production, our results suggest that purinergic stimulation of IMCD results in enhanced production and release of PGE2 in a COX-1-dependent fashion. Because PGE2 is known to affect transport of water, salt, and urea in IMCD, interaction of the purinergic system with the prostanoid system in IMCD can modulate handling of water, salt, and urea by IMCD and, thus, may constitute an AVP-independent regulatory mechanism.