Increase in sex-dependent expression of prolactin receptors after intrahepatic transplantation of H27 rat hepatoma cells.

Immunohistochemical study revealed overexpression of prolactin receptors in central and peripheral cells of intrahepatic grafts from H27 rat hepatoma without changes in compartmentalization compared to hepatocytes of intact animals. Experiments with gonadectomized animals showed that the hormonal regulation of prolactin receptors in both types of tumor cells does not differ from that in normal liver cells (positive estrogen-dependent regulation and negative androgen-dependent regulation).

Overexpression of prolactin receptors during intrahepatic transplantation of RS1 rat cholangiocellular carcinoma cells.

Immunohistochemical study showed that expression of prolactin receptors in intrahepatically transplanted cells of RS1 cholangiocellular carcinoma 2-fold exceeds that in cholangiocytes of intact rats. The number of prolactin receptors significantly increased in tumor cell nuclei of male and female animals. The RS1 transplant induced overexpression of prolactin receptors in hepatocytes and increased their number in nuclei of these cells.

[Approaches to the targeted intracellular delivery of photosensitizers in order to enhance their efficacy and cell specificity]. / Podkhody k napravlennoi vnutrikletochnoi dostavke fotosensibilizatorov dlia uvelicheniia ikh éffektivnosti i pridaniia kletochnoi spetsifichnosti.

The main physicochemical properties of photosensitizers used in the photodynamic therapy of cancer and their subcellular distribution after in vitro and in vivo administration were analyzed. It was shown that the effect of photosensitizers is realized at very short distances from the sites of their intracellular localization, and the sensitivities of different cellular compartments to the photocytotoxic action of photosensitizers are different. The necessity of intranuclear delivery of photosensitizers into the nuclei of target cells in order to enhance their efficacy and cell specificity was shown and the available approaches to the targeted delivery of photosensitizers were analyzed. The mechanisms of nucleocytoplasmic transport through the nuclear pore complex, which can be used for the delivery of photosensitizers inward the nucleus, are reviewed. Different modular transporters for photosensitizers comprising (i) a ligand module, which binds to an internalizable receptor overexpressed on the target cells, (ii) an intracellular localization signal, (iii) a carrier module, and (iv) an endosomolytic module were characterized. All these modules were shown to be fully functional within the chimeric polypeptide and the polypeptide as a whole. A significant enhancement of photocytotoxicity and cell specificity of photosensitizers delivered by these transporters were demonstrated. The transporters described represent a new generation of pharmaceuticals which can be widely used for targeted drug delivery.

Expression of prolactin receptors in human liver during cholestasis of different etiology and secondary liver cancer.

Indirect immunoperoxidase assay and computer analysis of photographic images revealed more intensive expression of prolactin receptors in hepatocytes of women compared to men. The intensity of expression was maximum in secondary liver cancer, high in obstructive jaundice of different etiology, and less pronounced in cholelithiasis. The expression of prolactin receptors in cholangiocytes was higher than in hepatocytes and was maximum during obstructive jaundice of different etiology. Cells of secondary tumors were characterized by low expression, while distant hepatocytes most intensively expressed prolactin receptors.

[Targeted intracellular site-specific drug delivery: photosensitizer targeting to melanoma cell nuclei]. / Napravlennaia vnutrikletochnaia dostavka lokal'no deistvuiushchikh lekarstv: spetsificheskaia dostavka fotosensibilizatorov v iadra kletok melanomy.

A number of drugs are regarded as possessing local activity because their effects take place at an extremely short distance from their location site in the cell. The response of different cellular compartments to these effects is different. Such substances as photosensitizers (PSs), which are used in photodynamic cancer therapy, should be targeted to the cell compartments where their effect is the most pronounced. This study describes the construction and properties of the chimeric modular recombinant transporters (MRTs) expressed in Escherichia coli and used for PS targeting. These constructs include (1) the alpha-melanocyte-stimulating hormone as a ligand module, which is internalized by the target cells (mouse melanoma); (2) the optimized SV40 large T-antigen nuclear localization signal; (3) the hemoglobin-like protein from E. coli as a carrier module; (4) the endosomolytic module, the translocation domain of the diphtheria toxin. These MRTs were used for PS targeting to the mouse melanoma cell nuclei, the most PS-damaged intracellular compartment, which resulted in a PS photocytotoxic effect increase of several orders of magnitude. In our opinion, MRTs, which target locally active drugs into the desired cell compartment and thereby enhance the drug response, represent a new generation of the pharmacological agents.

[Photodynamic effects of a concanavalin A-chlorin e6 conjugate on human fibroblasts]. / Fotodinamicheskoe deistvie kon"iugata konkanavalina A s khlorinom e6 na fibroblasty cheloveka.

To minimize the side effect of porphyrin photosensitizers and to reduce their active concentration, chlorine e6 was conjugated with concanavalin A. Photodynamic action of chlorine e6 and concanavalin A-chlorine e6 conjugate has been studied in human skin embryonic fibroblasts. The conjugate appeared to be 5 times more effective as compared to chlorine e6 due to concanavalin A-chlorine e6 endocytosis into intracellular compartments.

[Relation between the characteristic activity of the beta-adrenergic agonist isoproterenol and the percolation properties of cell membrane]. / Zavisimost' kharakteristicheskoi aktivnosti beta-adrenergicheskogo agonista izoproterenola ot perkoliatsionnykh svoistv plazmaticheskoi membrany kletki.

Variations in the intrinsic activity of 1-isoproterenol and in the percentage of high affinity beta-receptor complexes have been studied under a changes in the macrostructure of reticulocyte plasma membranes. The fluid lipid fraction have been reduced in the membranes for this by phospholipase A2/BSA treatment. It was accompanied by a progressive decrease in the fraction of beta-receptors that are able to form the high affinity complexes with 1-isoproterenol (receptor--regulatory N-protein complexes). Evaluated with the ability to activate the adenylate cyclase, the intrinsic activity of 1-isoproterenol was decreased from 1 to 0 under with conditions. This variations proved to correlate strongly with each other. Thus, changes in the membrane macrostructure may directly determine an efficiency of hormone actions.

[Dependence of hormonal stimulation of adenylate cyclase on the fraction of plasma membrane accessible to the lateral transport of adenylate cyclase complex proteins]. / Zavisimost' gormonal'noi stimuliatsii adenilattsiklazy ot doli plazmaticheskoi membrany, dostupnoi dlia lateral'nogo peremeshcheniia belkov adenilattsiklaznogo kompleksa.

Hormonal activation of the adenylate cyclase complex is associated with lateral mobility of proteins constituting this complex. Modification of interaction of the adenylate cyclase complex proteins due to variations in the "fluid" lipid fraction in cell membranes was studied. The decrease of percentage of "fluid" lipids in rat reticulocyte plasma membranes resulted in a decrease (up to a full stop) of interaction of beta-adrenoreceptors with regulatory N-proteins. The interaction of N-proteins with catalytic proteins was also blocked. On the other hand, an increase in the "fluid" lipid fraction led to a more intensive interaction. The observed phenomena do not result from functional damages of interacting proteins. Analysis of experimental results within the framework of the percolation theory suggests that hormonal activation of the adenylate cyclase complex depends on the "fluid" lipid fraction in the membrane and that the interacting proteins diffuse at distances comparable with the size of the cell membrane. The intrinsic activity of the beta-agonist isoproterenol changes from 1 to 0, depending on the "fluid" lipid fraction. The experimental data also suggest that there are no beta-receptors precoupled with N-proteins in rat reticulocyte membranes in vitro.