RESUMO
Tumor cells require increased adenosine triphosphate (ATP) to support anabolism and proliferation. The precise mechanisms regulating this process in tumor cells are unknown. Here, we show that the receptor for advanced glycation endproducts (RAGE) and one of its primary ligands, high-mobility group box 1 (HMGB1), are required for optimal mitochondrial function within tumors. We found that RAGE is present in the mitochondria of cultured tumor cells as well as primary tumors. RAGE and HMGB1 coordinately enhanced tumor cell mitochondrial complex I activity, ATP production, tumor cell proliferation and migration. Lack of RAGE or inhibition of HMGB1 release diminished ATP production and slowed tumor growth in vitro and in vivo. These findings link, for the first time, the HMGB1-RAGE pathway with changes in bioenergetics. Moreover, our observations provide a novel mechanism within the tumor microenvironment by which necrosis and inflammation promote tumor progression.
Assuntos
Complexo I de Transporte de Elétrons/metabolismo , Proteína HMGB1/metabolismo , Neoplasias Pancreáticas/patologia , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Trifosfato de Adenosina/biossíntese , Trifosfato de Adenosina/metabolismo , Animais , Butadienos/farmacologia , Antígeno CD24/genética , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Cicloeximida/farmacologia , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Metabolismo Energético , Inibidores Enzimáticos/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Proteína HMGB1/efeitos dos fármacos , Humanos , Inflamação/metabolismo , MAP Quinase Quinase 2/genética , MAP Quinase Quinase 2/metabolismo , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , NF-kappa B/efeitos dos fármacos , NF-kappa B/metabolismo , Nitrilas/farmacologia , Neoplasias Pancreáticas/metabolismo , Fosforilação/efeitos dos fármacos , Ligação Proteica/efeitos dos fármacos , Inibidores da Síntese de Proteínas/farmacologia , Interferência de RNA , RNA Interferente Pequeno/genética , Receptor para Produtos Finais de Glicação Avançada/genética , Rotenona/farmacologia , Transdução de Sinais , Receptor 2 Toll-Like/genética , Receptor 4 Toll-Like/genética , Microambiente Tumoral , DesacopladoresRESUMO
Repair proteins alter the local DNA structure during nucleotide excision repair (NER). However, the precise role of DNA melting remains unknown. A series of DNA substrates containing a unique site-specific BPDE-guanine adduct in a region of non-complementary bases were examined for incision by the Escherichia coli UvrBC endonuclease in the presence or absence of UvrA. UvrBC formed a pre-incision intermediate with a DNA substrate containing a 6-base bubble structure with 2 unpaired bases 5' and 3 unpaired bases 3' to the adduct. Formation of this bubble served as a dynamic recognition step in damage processing. UvrB or UvrBC may form one of three stable repair intermediates with DNA substrates, depending upon the state of the DNA surrounding the modified base. The dual incisions were strongly determined by the distance between the adduct and the double-stranded-single-stranded DNA junction of the bubble, and required homologous double-stranded DNA at both incision sites. Remarkably, in the absence of UvrA, UvrBC nuclease can make both 3' and 5' incisions on substrates with bubbles of 3-6 nucleotides, and an uncoupled 5' incision on bubbles of >/=>/=10 nucleotides. These data support the hypothesis that the E.coli and human NER systems recognize and process DNA damage in a highly conserved manner.
Assuntos
Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Dano ao DNA/genética , DNA Helicases , Reparo do DNA/fisiologia , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Escherichia coli , Sequência de Bases , Adutos de DNA/metabolismo , Pegada de DNA , Endodesoxirribonucleases/metabolismo , Escherichia coli/genética , Modelos Moleculares , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Permanganato de Potássio/metabolismo , Especificidade por SubstratoRESUMO
The synthesis of the formally monofunctional bis(platinum) complex [(Pt(NH3)3)mu-H2N(CH2)4NH2-(trans-PtCl(NH3)2)]3+ (1,0/t) is reported. The interactions of this species and the formally bifunctional bis(platinum) complex [(trans-PtCl(NH3)2)2H2N(CH2)4NH2]Cl2(1,1/t,t) with DNA were investigated. Comparison was made with the monomeric [PtCl(dien)]Cl, (Pt(DIEN)), and cis-[PtCl2(NH3)2], (cis-DDP). The initial rates of reaction with small self-complementary oligonucleotides 5'-ATATATN4ATATAT-3' (N4 = GCGC and N4 = GGCC) were calculated. For all compounds, the GGCC oligonucleotide reacted faster than the GCGC counterpart. The order of reactivity of the platinum compounds for the GCGC oligonucleotide was 1,1/t,t > 1,0/t > Pt(DIEN) > cis-DDP. The reaction of 1,0/t and 1,1/t,t with poly(dG-dC).poly(dG-dC) was also investigated using circular dichroism (CD) spectroscopy where both compounds were shown to induce a B-->Z conformational change.