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    Unusual Enhancement of Doxorubicin Activity on Co-Delivery with Polyhedral Oligomeric Silsesquioxane (POSS)
    (Basel : MDPI, 2017) Sobierajska, Ewelina; Konopka, Malgorzata; Janaszewska, Anna; Piorecka, Kinga; Blauz, Andrzej; Klajnert-Maculewicz, Barbara; Stanczyk, Maciej; Stanczyk, Wlodzimierz A.
    Polyhedral oligomeric silsesquioxane (POSS), bearing eight 3-chloroammoniumpropyl substituents, was studied as a potential nanocarrier in co-delivery systems with doxorubicin (DOX). The toxicity of doxorubicin and POSS:DOX complexes at four different molar ratios (1:1; 1:2, 1:4, 1:8) towards microvascular endothelial cells (HMEC-1), breast cancer cells (MCF-7), and human cervical cancer endothelial cells (HeLa) was determined. The rate of penetration of the components into the cells, their cellular localization and the hydrodynamic diameter of the complexes was also determined. A cytotoxicity profile of POSS:DOX complexes indicated that the POSS:DOX system at the molar ratio of 1:8 was more effective than free DOX. Confocal images showed that DOX co-delivery with POSS allowed for more effective penetration of doxorubicin through the cell membrane. Taking all the results into account, it can be claimed that the polyhedral oligomeric silsesquioxane (T8-POSS) is a promising, complex nanocarrier for doxorubicin delivery.
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    Complexing Methylene Blue with Phosphorus Dendrimers to Increase Photodynamic Activity
    (Basel : MDPI, 2017) Dabrzalska, Monika; Janaszewska, Anna; Zablocka, Maria; Mignani, Serge; Majoral, Jean Pierre; Klajnert-Maculewicz, Barbara
    The efficiency of photodynamic therapy is limited mainly due to low selectivity, unfavorable biodistribution of photosensitizers, and long-lasting skin sensitivity to light. However, drug delivery systems based on nanoparticles may overcome the limitations mentioned above. Among others, dendrimers are particularly attractive as carriers, because of their globular architecture and high loading capacity. The goal of the study was to check whether an anionic phosphorus dendrimer is suitable as a carrier of a photosensitizer—methylene blue (MB). As a biological model, basal cell carcinoma cell lines were used. We checked the influence of the MB complexation on its singlet oxygen production ability using a commercial fluorescence probe. Next, cellular uptake, phototoxicity, reactive oxygen species (ROS) generation, and cell death were investigated. The MB-anionic dendrimer complex (MB-1an) was found to generate less singlet oxygen; however, the complex showed higher cellular uptake and phototoxicity against basal cell carcinoma cell lines, which was accompanied with enhanced ROS production. Owing to the obtained results, we conclude that the photodynamic activity of MB complexed with an anionic dendrimer is higher than free MB against basal cell carcinoma cell lines.
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    Conjugate of PAMAM Dendrimer, Doxorubicin and Monoclonal Antibody—Trastuzumab: The New Approach of a Well-Known Strategy
    (Basel : MDPI, 2018) Marcinkowska, Monika; Sobierajska, Ewelina; Stanczyk, Maciej; Janaszewska, Anna; Chworos, Arkadiusz; Klajnert-Maculewicz, Barbara
    The strategy utilizing trastuzumab, a humanized monoclonal antibody against human epidermal growth receptor 2 (HER-2), as a therapeutic agent in HER-2 positive breast cancer therapy seems to have advantage over traditional chemotherapy, especially when given in combination with anticancer drugs. However, the effectiveness of single antibody or antibody conjugated with chemotherapeutics is still far from ideal. Antibody–dendrimer conjugates hold the potential to improve the targeting and release of active substance at the tumor site. In the present study, we developed and synthesized PAMAM dendrimer–trastuzumab conjugates carrying doxorubicin (dox) specifically to cells overexpressing HER-2. 1HNMR, FTIR and RP-HPLC were used to characterize the products and analyze their purity. Toxicity of PAMAM–trastuzumab and PAMAM–dox–trastuzumab conjugates compared with free trastuzumab and doxorubicin towards HER-2 positive (SKBR-3) and negative (MCF-7) human breast cancer cell lines was determined using MTT assay. Furthermore, the cellular uptake and cellular localization were studied by flow cytometry and confocal microscopy, respectively. A cytotoxicity profile of above mentioned compounds indicated that conjugate PAMAM–dox–trastuzumab was more effective when compared to free drug or the conjugate PAMAM–trastuzumab. Moreover, these results reveal that trastuzumab can be used as a targeting agent in PAMAM–dox–trastuzumab conjugate. Therefore PAMAM–dox–trastuzumab conjugate might be an interesting proposition which could lead to improvements in the effectiveness of drug delivery systems for tumors that overexpress HER-2.