RESUMO
Cell hybrids obtained by fusing mouse PCC4azal teratocarcinoma cells and spleen cells induced to proliferation and treated with the demethylating agent 5-azacytidine prior to fusion are described. The obtained hybrids demonstrated no expression of T lymphocyte marker genes CD11 and CD45, which indicates possible somatic nucleus reprogramming by factors present in teratocarcinoma cells. Irrespective of culture conditions, cell hybrids demonstrated a relatively stable chromosome number: they lost on average no more than four chromosomes after 30 passages. Culturing in medium containing hypoxanthine, aminopterin, and thymidine (selective conditions) decreased the differentiation capacity of cell hybrids compared to nonselective conditions, which is likely due to the inhibition of their metabolism. For the first time, teratocarcinoma cell hybrid differentiation into cardiomyocytes under the influence of DMSO has been demonstrated in vitro.
Assuntos
Diferenciação Celular/efeitos dos fármacos , Crioprotetores/farmacologia , Dimetil Sulfóxido/farmacologia , Hibridomas/metabolismo , Miócitos Cardíacos/metabolismo , Baço/metabolismo , Teratocarcinoma/metabolismo , Animais , Antígenos de Diferenciação/biossíntese , Azacitidina/farmacologia , Antígenos CD11/biossíntese , Técnicas de Cultura de Células , Fusão Celular/métodos , Linhagem Celular Tumoral , Cromossomos de Mamíferos/genética , Metilação de DNA/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Hibridomas/patologia , Antígenos Comuns de Leucócito/biossíntese , Camundongos , Miócitos Cardíacos/patologia , Baço/patologia , Linfócitos T/metabolismo , Linfócitos T/patologia , Teratocarcinoma/patologiaRESUMO
The study is concerned with proapoptotic properties of chimera peptides which incorporate sequences of inhibitors of cyclin kinases p161NK4a and p21CIP/WAF1 as well as internalized sequences (Antp and tat). Sequences of the p16 type appeared to be more cytotoxic than the p21 one. Cytotoxic effect proved dependent on orientation with respect to the C or N terminal point of a polypeptide chain rather than on chimera sequence extent. Although p16 endogenous synthesis did not influence chimera peptide levels, apoptosis did not take place in certain cellular lines. Due to the rather unsophisticated nature of such synthesis, it might be used in designing individually-tailored chemotherapeutic drugs.
Assuntos
Proteína do Homeodomínio de Antennapedia/metabolismo , Apoptose , Quimera , Inibidor p16 de Quinase Dependente de Ciclina/farmacologia , Inibidor de Quinase Dependente de Ciclina p21/farmacologia , Produtos do Gene tat/metabolismo , Sequência de Aminoácidos , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Inibidor p16 de Quinase Dependente de Ciclina/biossíntese , Inibidor p16 de Quinase Dependente de Ciclina/genética , Inibidor de Quinase Dependente de Ciclina p21/biossíntese , Inibidor de Quinase Dependente de Ciclina p21/genética , Regulação Neoplásica da Expressão Gênica , Genes p16 , Genes p53 , Humanos , Células Jurkat , Dados de Sequência Molecular , Peptídeos/farmacologiaRESUMO
We studies the activities of ribosomal genes (nucleolus forming regions of chromosomes) at successive stages of cultivation of the mouse R1 embryonic stem cells. The total number and number of active nucleolar organizers were estimated by means of in situ hybridization with mouse rDNA probes and argentophilic staining of nucleolus forming chromosomes regions from the 16th until the 32nd passages. The data we obtained suggest that the total number of nucleolar organizers per metaphase plate was constant (as a rule, eight), while the mean number of active nucleolar organizers progressively increased from the early (16th) to the late (32nd) passages: 5.2 +/- 0.4 versus 7.4 +/- 0.9 argentophilic organizers per cell. Cell heterogeneity by the number of active nucleolar organizers also increased during the late passages. Taken together, these data suggest activation of DNA transcription and synthesis of ribosomes during cultivation of mouse R1 embryonic stem cells. Based on the experimental and published data, it has been proposed that activation of ribosomal genes correlates in time with a decreased capacity of embryonic stem cells for pluripotent differentiation.