[Epithelial to Mesenchymal Transition Marker in 2D and 3D Colon Cancer Cell Cultures in the Presence of Laminin 332 and 411].

Received August 28, 2018; revised October 10, 2018; accepted November 6, 2018 The loss of apical-basal cell polarity is a necessary stage of the epithelial-mesenchymal transition (EMT). Polarized epithelial cells interact with the basement membrane (BM) and, in particular, with laminins, the major components of BM. Here, we examined the effect of the transition of colon cancer cells from 2D polarized state to non-polarized 3D state on the expression of EMT associated genes, as well as the role of laminins 332 and 411 (LM-332 and LM-411) in this process. The three studied cell lines, HT-29, HCT-116 and RKO, were found to have different sensitivity to cultivation conditions (2D to 3D changes) and to addition of laminins. One of the possible reasons for this maybe a difference in the initial 2D state of the cells. In particular, it was shown that the cell lines were at different EMT stages. HT-29 exhibited more epithelial expression profile, RKO was more mesenchymal, and HCT-116 was in an intermediate state. The most laminin-sensitive cell line was HCT-116. The magnitude and the specificity of cell response to LM-332 and LM-411 depended on the expression pattern of laminins' receptors. EMT gene expression profile was not substantially changed neither during the transition from 2D to 3D state, nor the presence of laminins' isoforms. However, we detected changes in expression of SNAI1 and ZEB1 genes encoding transcription factors that control the EMT process. Notably, in all three studied cell lines, the expression of SNAI1 was enhanced in response to laminin treatment.

Effects of Laminins 332 and 411 on the Epithelial-Mesenchymal Status of Colorectal Cancer Cells.

The effects of laminins 332 and 411 (LM-332 and LM-411) on the epithelial-mesenchymal transformation of colorectal cancer cells (lines HT-29, HCT-116, and RKO) with different metastatic potential were studied. Culturing of RKO cells on both laminins was associated with modification of the cell shape, which became more spindle-like or stellate, and with higher expression of EMT-associated transcription factors SNAI1 and ZEB1. In addition, culturing on LM-332 led to a decrease in the expression of laminin α5 chain (LAMA5), while culturing on LM-411 led to an increase in the expression of a cell-cell junction component (DSP). Culturing of HT-29 cells on LM-332 was associated with the formation of more close contacts between the cells and by a higher expression of epithelial markers (CDH1 and DSP genes) and a decrease in SNAI1 expression. Culturing of HCT-116 cells on both laminins led to a decrease in FN1 expression, on LM-332 - to an increase in laminin α4 chain (LAMA4) expression, and on LM-411 - to a lesser expression of LAMA4 and transcription factors SNAI2 and ZEB1. These data indicated that colorectal cancer cell adhesion to laminins contributed to the probability of epithelial-mesenchymal transformation of cells. The direction of this transformation seemed to depend on the initial characteristics of the cells.

[Laminins in Metastatic Cancer].

Laminins are a family of extracellular heterotrimeric glycoproteins that are the main structural component of basement membranes (BMs), perform a barrier function, and are important for adhesion, differentiation, migration, and resistance to apoptosis of various cells, including cancer cells. The review summarizes the current knowledge of how laminins produced by cancer and normal cells influence the key stages of carcinogenesis. Laminin 332 (LN-332) and LN-111 enhance proliferation of certain cancer cells and increase the tumour growth. LN-111 increases resistance to apoptosis, induces differentiation, and inhibits the epithelial-mesenchymal transition (EMT) of cancer cells. LN-332 is associated with higher adhesion and higher migration potential of cancer cells. LN-411 and LN-421 significantly increase motility of cancer cells. LN-332 and LN-511 facilitate cell-cell adhesion and affect the efficacy of cell-cell interactions. The laminin chains α4 and α5 are important for the development and function of blood and lymphatic vessels. The expression ratio of the α4 and α5 laminin chains defines the BM permeability to leukocytes and, presumably, cancer cells in blood and lymphatic vessels. Interactions between LN-511 and α2-containing laminins enhance self-renewal and survival of circulating cancer stem cells. Moreover, laminins are involved in the formation of premetastatic niches and new colonies. Endogenous expression of the α4 laminin chain stimulates proliferation of individualised circulating cancer cells in vitro and in vivo and facilitates micrometastasis.

Binding of Hoechst 33258 and its derivatives to DNA.

In the present work, we employed UV-VIS spectroscopy, fluorescence methods, and circular dichroism spectroscopy (CD) to study the interaction of dye Hoechst 33258, Hoechst 33342, and their derivatives to poly[d(AT)].poly[d(AT)], poly(dA).poly(dT), and DNA dodecamer with the sequence 5'-CGTATATATACG-3'. We identified three types of complexes formed by Hoechst 33258, Hoechst 33342, and methylproamine with DNA, corresponding to the binding of each drug in monomer, dimer, and tetramer forms. In a dimer complex, two dye molecules are sandwiched in the same place of the minor DNA groove. Our data show that Hoechst 33258, Hoechst 33342, and methylproamine also form complexes of the third type that reflects binding of dye associates (probably tetramers) to DNA. Substitution of a hydrogen atom in the ortho position of the phenyl ring by a methyl group has a little effect on binding of monomers to DNA. However it reduces strength of binding of tetramers to DNA. In contrast, a Hoechst derivative containing the ortho-isopropyl group in the phenyl ring exhibits a low affinity to poly(dA).poly(dT) and poly[d(AT)].poly[d(AT)] and binds to DNA only in the monomer form. This can be attributed to a sterical hindrance caused by the ortho-isopropyl group for side-by-side accommodation of two dye molecules in the minor groove. Our experiments show that mode of binding of Hoechst 33258 derivatives and their affinity for DNA depend on substituents in the ortho position of the phenyl ring of the dye molecule. A statistical mechanical treatment of binding of Hoechst 33258 and its derivatives to a polynucleotide lattice is described and used for determination of binding parameters of Hoechst 33258 and its derivatives to poly[d(AT)].poly[d(AT)] and poly(dA).poly(dT).

[Use of information technology in oncology practice at the Moscow Research Institute of Diagnosis and Surgery]. / Informatsionnye tekhnologii v onkologicheskoi praktike Moskovskogo NII Diagnostiki i Khirurgii.

The report deals with introduction of such modern information technologies as electronic processing of documents and access to INTERNET data into diagnostic and therapeutic practice.