The activation of extracellular signal-regulated kinases (ERK1/2) has been associated with specific outcomes. Sustained activation of ERK1/2 by nerve growth factor (NGF) is associated with translocation of ERKs to the nucleus of PC12 cells and precedes their differentiation into sympathetic-like neurons whereas transient activation by epidermal growth factor (EGF) leads to cell proliferation. It was demonstrated that different growth factors initiating the same cellular signaling pathways may lead to the different cell destiny, either to proliferation or to the inhibition of mitogenesis and apoptosis. Thus, further investigation on kinetic differences in activation of certain signal cascades in different cell types by biologically different agents are necessary for understanding the mechanisms as to how cells make a choice between proliferation and differentiation.It was reported that chitinase 3-like 1 (CHI3L1) protein promotes the growth of human synovial cells as well as skin and fetal lung fibroblasts similarly to insulin-like growth factor 1 (IGF1). Both are involved in mediating the mitogenic response through the signal-regulated kinases ERK1/2. In addition, CHI3L1 which is highly expressed in different tumors including glioblastomas possesses oncogenic properties. As we found earlier, chitinase 3-like 2 (CHI3L2) most closely related to human CHI3L1 also showed increased expression in glial tumors at both the RNA and protein levels and stimulated the activation of the MAPK pathway through phosphorylation of ERK1/2 in 293 and U87 MG cells. The work described here demonstrates the influence of CHI3L2 and CHI3L1 on the duration of MAPK cellular signaling and phosphorylated ERK1/2 translocation to the nucleus. In contrast to the activation of ERK1/2 phosphorylation by CHI3L1 that leads to a proliferative signal (similar to the EGF effect in PC12 cells), activation of ERK1/2 phosphorylation by CHI3L2 (similar to NGF) inhibits cell mitogenesis and proliferation.

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More than forty genes with considerably increased expression in glioblastoma as compared to normal human brain were identified by SAGE. One of the most prominent among them was CHI3L2 (YKL-39) gene, which encodes 39 kDa chitinase-like protein.Northern blot hybridization confirmed the data of SAGE for the majority of glioblastomas. Anaplastic astrocytomas could be divided on two groups: in one of them the YKL-39 expression was completely undetectable, but in the other group quite high contents of YKL-39 mRNA were detected. In this study, preliminary data show that patients with undetectable expression of YKL-39 in anaplastic astrocytomas did not have recurrent tumors quite long (more than 2-3 years) period of time. YKL-39 RNA has not been detected in diffuse astrocytomas and in all (but one) samples of normal brain. Increased expression of YKL-39 gene in glioblastomas was shown also at the protein level. Western blots did not shown simultaneous production of YKL-39 and YKL-40, in spite of having high degree of their sequence identity. Increased expression of YKL-39 in subsets of patients with glial tumors, reported here for the first time, together with abnormal increase of the YKL-40 gene expression may be a novel molecular marker for glial tumors.

Transplantation of placenta-derived multipotent cells (PDMCs) is a promising approach for cell therapy to treat inflammation-associated colon diseases. However, the effect of PDMCs on colon cancer cells remains unknown. The aim of the present study was to characterize PDMCs obtained from human (hPDMCs) and rat (rPDMCs) placentas and to evaluate their impact on colon cancer progression in rats. PDMCs were obtained from human and rat placentas by tissue explant culturing. Stemness- and trophoblast-related gene expression was studied using reverse transcription-polymerase chain reaction (RT-PCR), and surface markers and intracellular proteins were detected using flow cytometry and immunofluorescence, respectively. Experimental colon carcinogenesis was induced in male albino Wistar rats by injecting 20 mg/kg dimethylhydrazine (DMH) once a week for 20 consecutive weeks. The administration of rPDMCs and hPDMC was performed at week 22 after the initial DMH-injection. All animals were sacrificed through carbon dioxide asphyxiation at week 5 after cell transplantation. The number and size of each tumor lesion was calculated. The type of tumor was determined by standard histological methods. Cell engraftment was determined by PCR and immunofluorescence. Results demonstrated that rPDMCs possessed the immunophenotype and differentiation potential inherent in MSCs; however, hPDMCs exhibited a lower expression of cluster of differentiation 44 and did not express trophoblast-associated genes. The data of the present study indicated that PDMCs may engraft in different tissues but do not significantly affect DMH-induced tumor growth during short-term observations.

The purpose of this study was to investigate the immunophenotypes and gene expression profile of high proliferative placenta-derived multipotent cells (PDMCs) population at different stages of culture. We demonstrated that the colonies resulting from single cells were either positive or negative for CK7, whereas only PDMC clones with weak CK7 expression (CK7low-clones) were highly proliferative. Interestingly, vimentin positive (Vim+) placental stromal mesenchymal cells did not express CK7 in situ, but double CK7+Vim+ cells detection in tissue explants and explants outgrowth indicated CK7 inducible expression in vitro. PCNA presence in CK7+Vim+ cells during placental explants culturing confirmed belonging of these cells to proliferative subpopulation. Transcription factors CDX2 and EOMES were expressed in both CK7low-clones and subset of stromal mesenchymal cells of first-trimester placental tissue in situ. Meanwhile, CK7low -clones and stromal mesenchymal cells of full-term placental tissue in situ expressed ERG heterogeneously. SPP1, COL2A1, and PPARG2 mesodermal-related genes expression by CK7low-clones additionally confirms their mesenchymal origin. Inherent stem cell-related gene expression (IFTM3, POU5F1, and VASA) in CK7low-clones might indicate their enrichment for progenitors. Finally, in CK7low-clones we observed expression of such trophoblast-associated genes as CGB types I and II, fusogenic ERVW-1, GCM1, and GATA3. Thus, our results indicate that PDMCs acquired the representative immunophenotype signature under culture conditions.

Aim. To characterize the immortalized 293 cell line after stable transfection with human oncogene (CHI3L1). Methods. 293 cells, stably transfected with pcDNA3.1_CHI3L1, and 293 cells, stably transfected with pcDNA3.1 as a negative control, were used throughout all experiments. The clones of CHI3L1-expressing 293 cells and 293 cells, transfected with pcDNA3.1, were analyzed by immunofluorescence and confocal microscopy. Cell proliferation was measured using MTT assay; analyses of ERK1/2 and AKT activation and their cellular localization were performed with anti-phospho-ERK and anti-phospho-AKT antibodies. Specific activation of MAP and PI3 kinases was measured by densitometric analysis of Western-blot signals. Results. The obtained results show quite modest ability of CHI3L1 to stimulate cell growth and reflect rather an improved cellular plating efficiency of the 293 cells stably transfected with pcDNA3.1_CHI3L1 as compared to the 293 cells transfected with an «empty» vector. ERK1/2 and AKT are activated in the 293_CHI3L1 cells. In these cells phosphorylated ERK1/2 were localized in both cell cytoplasm and nuclei while AKT only in cytoplasm. The 293_CHI3L1 cells differed from the 293 cells, transfected with an «empty» vector, in their size and ability to adhere to the culture plates. Conclusions. The overexpression of CHI3L1 is likely to have an important role in tumorigenesis via a mechanism which involves activation of PI3K and ERK1/2 pathways. The tumors which can be induced by orthotopic implantation of the transformed human cells with overexpressed human oncogene CHI3L1 into the rat brain can be used as a target for anticancer drug development

Transplantation of placenta-derived multipotent cells (PDMCs) is a promising treatment method for many diseases. However, the impact of PDMCs on colon cancer has not yet been studied. PDMCs were obtained from rat placentas by culturing tissue explants. Colon cancer was experimentally induced in male albino Wistar rats by administering 20 mg/kg dimethylhydrazine (DMH) once a week for 20 consecutive weeks. The administration of the PDMCs was performed at the 20th week after the first DMH injection. The number and size of each tumour lesion were calculated in the 5th week after transplantation. The tumour type was determined by standard histological methods. To study the engraftment of PDMCs in the body of rats, the cells were transduced with enhanced green fluorescent protein. Cell engraftment was determined by assessing the presence of EGFP by PCR and immunohistochemistry. Survival of all rats was monitored daily. Allogeneic transplantation of PDMCs to rats at middle phase of DMH-induced colon carcinogenesis did not significantly influence the number of neoplasms and the parameters of mean and total tumour area, but led to an increase in size of the most invasiveness tumours. Intravenous allogeneic transplantation of PDMCs reduced the survival rate of rats with colon cancer by 17 days. PDMCs from rats engrafted into tissues of the normal intestine, tumours, lungs, liver, and spleen of rats for five weeks after intravenous transplantation. These results suggest that intravenous allogeneic transplantation of PDMCs promotes colon cancer progression and has a negative impact on survival of rats.

Aim. To determine 293 and U373 cell response and ERK1/2 activation profile after CHI3L1 or CHI3L2 treatment. Methods. Specific activation and localization of ERK1/2 kinases after CHI3L1 or CHI3L2 addition to unsupplemented cell medium were evaluated by Western blots, immunofluorescence and confocal microscopy. To determine whether CHI3L1 or CHI3L2 can enhance mitogenesis, [3H]thymidine incorporation in cellular DNA was measured. Results. The obtained results show that ERK1/2 phosphorylation was stimulated in both cell types (293 and U373 cells) following addition of CHI3L2 or CHI3L1 in dose- and time-dependent manner. Unexpectedly, in opposite to CHI3L1, the dose-dependent decreasing of measured mitogenesis parameters was observed in 293 and U373 cells. In both cell types the treatment with CHI3L2 gave more sustained than CHI3L1 MAPK-pathway activation with prolonged phospho-ERK1/2 nuclear accumulation in 293 cells. Conclusions. In contrast to the activation of ERK1/2 phosphorylation by CHI3L1 cell treatment, that leads to a proliferative signal, the activation of these kinases by CHI3L2 addition inhibits cell mitogenesis and proliferation in serum starved 293 and U373 cells