AimTo develop specific fluorescent markers for melanoma tumor visualization, which would provide high selectivity and reversible binding pattern, by the use of carbohydrate-recognizing proteins, lectins, combined with the physical ability for imaging deep in the living tissues by utilizing red and near infrared fluorescent properties of specific rare-earth doped nanocrystals (NC).MethodsB10F16 melanoma cells were inoculated to C57BL/6 mice for inducing experimental melanoma tumor. Tumors were removed and analyzed by lectin-histochemistry using LABA, PFA, PNA, HPA, SNA, GNA, and NPL lectins and stained with hematoxylin and eosin. NPL lectin was conjugated to fluorescent NaGdF4:Eu3+-COOH nanoparticles (5 nm) via zero length cross-linking reaction, and the conjugates were purified from unbound substances and then used for further visualization of histological samples. Fluorescent microscopy was used to visualize NPL-NaGdF4:Eu3+ with the fluorescent emission at 600-720 nm range.ResultsNPL lectin selectively recognized regions of undifferentiated melanoblasts surrounding neoangiogenic foci inside melanoma tumor, PNA lectin recognized differentiated melanoblasts, and LCA and WGA were bound to tumor stroma regions. NPL-NaGdF4:Eu3+ conjugated NC were efficiently detecting newly formed regions of melanoma tumor, confirmed by fluorescent microscopy in visible and near infrared mode. These conjugates possessed high photostability and were compatible with convenient xylene-based mounting systems and preserved intensive fluorescent signal at samples storage for at least 6 months.ConclusionNPL lectin-NaGdF4:Eu3+ conjugated NC permitted distinct identification of contours of the melanoma tissue on histological sections using red excitation at 590-610 nm and near infrared emission of 700-720 nm. These data are of potential practical significance for development of glycans-conjugated nanoparticles to be used for in vivo visualization of melanoma tumor.

Europium doped nanocrystals can be optimized to be successfully used as visualization markers for i.e. melanoma tumor.

Two treatment schemes (vinblastine and vinblastin in combination with sapogeninlike substance (SLS) isolated from the greater celandine seeds) were applied towards murine NK/Ly lymphoma, and their therapeutic effects were compared. It was revealed that at early stages of tumor growth, there was no significant difference in tumor suppressive effect of two treatment schemes. Potentiating effect of SLS in combined application with vinblastine manifested in delayed results of treatment, i.e. in more then 60 days after inoculation of tumor cells. Clinically, it was expressed in more effective suppression of tumor development after the repeated inoculation of tumor cells, as well as in preventing the appearance of solid tumor nodes, better recovery and survival of the treated mice. Quantitative evaluation of tumor cell damage was performed by using cell morphometry methods which revealed higher proportion of injured cells at the application of vinblastine-SLS mixture. Low toxicity of SLS from the greater celandine seeds, together with its enhancing effect upon the curative action of vinblastine, permits suggesting a perspectiveness of using SLS as an adjuvant in tumor chemotherapy.

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