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Background/Objectives: Doxorubicin (Dox) is an anticancer drug used in the treatment of a wide range of solid tumors; however, Dox causes systemic toxicity and irreversible cardiotoxicity. The design of a new nanosystem that allows for the control of Dox loading and delivery results is a powerful tool to control Dox release only in cancer cells. For this reason, supramolecular self-assembly was performed between a poly(amidoamine) (PAMAM) dendrimer decorated with four β-cyclodextrin (βCD) units (PAMAM-βCD) and an adamantane–hydrazone–doxorubicin (Ad-h-Dox) prodrug. Methods: The formation of inclusion complexes (ICs) between the prodrug and all the βCD cavities present on the surface of the PAMAM-βCD dendrimer was followed by 1H-NMR titration and corroborated by 2D NOESY experiments. A full characterization of the supramolecular assembly was performed in the solid state by thermal analysis (DSC/TGA) and scanning electron microscopy (SEM) and in solution by the DOSY NMR technique in D2O. Furthermore, the Dox release profiles from the PAMAM-βCD/Ad-h-Dox assembly at different pH values was studied by comparing the efficiency against a native βCD/Ad-h-Dox IC. Additionally, in vitro cytotoxic activity assays were performed for the nanocarrier alone and the two supramolecular assemblies in different carcinogenic cell lines. Results: The PAMAM-βCD/Ad-h-Dox assembly was adequately characterized, and the cytotoxic activity results demonstrate that the nanocarrier alone and its hydrolysis product are innocuous compared to the PAMAM-βCD/Ad-h-Dox nanocarrier that showed cytotoxicity equivalent to free Dox in the tested cancer cell lines. The in vitro drug release assays for the PAMAM-βCD/Ad-h-Dox system showed an acidic pH-dependent behavior and a prolonged profile of up to more than 72 h. Conclusions: The design of PAMAM-βCD/Ad-h-Dox consists of a new controlled and prolonged Dox release system for potential use in cancer treatment. [ABSTRACT FROM AUTHOR]

Simple Summary: Glucotoxicity is a condition that leads to β-cell death, driving a decrease in insulin secretion and leading to hyperglycemia and, eventually, diabetes. Here, we investigate whether connexin Cx30.2 could protect against glucotoxicity-induced apoptosis in β cells. We found that RIN-m5F β cells exposed to high glucose exhibited increased Cx30.2 protein expression. Interestingly, decreased expression of Cx30.2 by specific siRNAs resulted in augmented β-cell death, suggesting that Cx30.2 has an important role in maintaining cell survival during glucotoxicity. Overall, Cx30.2 could be an attractive pharmacological target to avoid high glucose-induced β-cell apoptosis. Glucotoxicity may exert its deleterious effects on pancreatic β-cell function via a myriad of mechanisms, leading to impaired insulin secretion and, eventually, type 2 diabetes. β-cell communication requires gap junction channels to be present among these cells. Gap junctions are constituted by transmembrane proteins of the connexins (Cxs) family. Two Cx genes have been identified in β cells, Cx36 and Cx30.2. We have found evidence that the glucose concentration on its own is sufficient to regulate Cx30.2 gene expression in mouse islets. In this work, we examine the involvement of the Cx30.2 protein in the survival of β cells (RIN-m5F). Methods: RIN-m5F cells were cultured in 5 mM D-glucose (normal) or 30 mM D-glucose (high glucose) for 24 h. Cx30.2 siRNAs was used to downregulate Cx30.2 expression. Apoptosis was measured by means of TUNEL, an annexin V staining method, and the cleaved form of the caspase-3 protein was determined using Western blot. Results: High glucose did not induce apoptosis in RIN-m5F β cells after 24 h; interestingly, high glucose increased the Cx30.2 total protein levels. Moreover, this work found that the downregulation of Cx30.2 expression in high glucose promoted apoptosis in RIN-m5F cells. Conclusion: The data suggest that the upregulation of Cx30.2 protects β cells from hyperglycemia-induced apoptosis. Furthermore, Cx30.2 may be a promising avenue of therapeutic investigation for the treatment of glucose metabolic disorders. [ABSTRACT FROM AUTHOR]

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Background: D3CLP (9-[(3-chloro)phenylamine]-2-[3-(diethylamine)propylamine]thiazolo[5,4-b]quinoline) is a potent cytotoxic thiazolo[5,4-b]quinoline synthetic derivative that induces apoptosis of leukemia cells, while it displays low toxicity towards non-tumoral cells. The aim of this study was to determine if D3CLP can enhance the cytotoxicity of other antineoplastic drugs., Materials and Methods: Leukemia, breast and cervical cancer cell lines were exposed to D3CLP-alone or in combination with imatinib, tamoxifen or cisplatin, respectively. Cell viability after treatment was evaluated by the MTT assay, and cell death by the TUNEL assay. The effects of combined treatments were analyzed by combination index and isobolographic analysis., Results: Antiproliferative activity results indicate that D3CLP in combination with antineoplastic drugs induced a synergistic effect, at 3:1 and 1:1 ratios for D3CLP plus imatinib in K-562 leukemia cells, and at a 3:1 ratio for D3CLP with cisplatin in HeLa cells, as determined by their combination index. Furthermore, isobolographic analysis demonstrated a significant synergism for a 3:1 combination ratio of D3CLP with cisplatin in HeLa cells. In addition, TUNEL assay suggests cell death by apoptosis of HeLa cells after treatment with D3CLP and its combination with cisplatin at a 3:1 ratio., Conclusion: Overall the results indicate that D3CLP, in combined preparation with antineoplastic drugs, is a good candidate for pre-clinical studies in the treatment of different carcinoma cell types.

To identify when during fetal development connexins (Cxs) 26 (Cx26) 32 (Cx32), and 36 (Cx36) begin to be expressed, as well as to characterize their spatial distribution, real time polymerase chain reaction and immunolabeling studies were performed. Total RNA from mouse pancreases at 13 and 18 days postcoitum (dpc) and 3 days postpartum (dpp) was analyzed. In addition, pancreatic sections of mouse at 13, 14, 15, 16, 18 dpc and 3 dpp and of rat at term were double labeled with either anti-insulin or anti-α-amylase and anti-Cx26 or -Cx32 or -Cx36 antibodies and studied with confocal microscopy. From day 13 dpc, Cxs 26, 32, and 36 transcripts were identified and their levels increased with age. At 13-14 dpc, Cxs 26 and 32 were localized in few acinar cells, whereas Cx36 was distributed in small beta cell clumps. From day 14 dpc onwards, the number of labeled cells and relative immunofluorescent reactivity of all three Cxs at junctional membranes of the respective cell types increased. Cxs 26 and 32 colocalized in fetal acinar cells. In rat pancreas at term, a similar connexin distribution was found. Relative Cxs levels evaluated by immunoblotting also increased (two-fold) in pancreas homogenates from day 18 dpc to 3 dpp. The early cell specific, wide distribution, and age dependent expression of Cxs 26, 32, and 36 during fetal pancreas ontogeny suggests their possible involvement in pancreas differentiation and prenatal maturation., (Copyright © 2012 Wiley Periodicals, Inc.)