RESUMO
G-quadruplex ligands exert their antiproliferative effects through telomere-dependent and telomere-independent mechanisms, but the inter-relationships among autophagy, cell growth arrest and cell death induced by these ligands remain largely unexplored. Here, we demonstrate that the G-quadruplex ligand 20A causes growth arrest of cancer cells in culture and in a HeLa cell xenografted mouse model. This response is associated with the induction of senescence and apoptosis. Transcriptomic analysis of 20A treated cells reveals a significant functional enrichment of biological pathways related to growth arrest, DNA damage response and the lysosomal pathway. 20A elicits global DNA damage but not telomeric damage and activates the ATM and autophagy pathways. Loss of ATM following 20A treatment inhibits both autophagy and senescence and sensitizes cells to death. Moreover, disruption of autophagy by deletion of two essential autophagy genes ATG5 and ATG7 leads to failure of CHK1 activation by 20A and subsequently increased cell death. Our results, therefore, identify the activation of ATM by 20A as a critical player in the balance between senescence and apoptosis and autophagy as one of the key mediators of such regulation. Thus, targeting the ATM/autophagy pathway might be a promising strategy to achieve the maximal anticancer effect of this compound.
Assuntos
Apoptose/efeitos dos fármacos , Proteínas Mutadas de Ataxia Telangiectasia , Autofagia/efeitos dos fármacos , Senescência Celular/efeitos dos fármacos , Quadruplex G , Neoplasias/patologia , Células A549 , Animais , Apoptose/genética , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Autofagia/genética , Linhagem Celular Tumoral , Senescência Celular/genética , Dano ao DNA/efeitos dos fármacos , Células HeLa , Humanos , Ligantes , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Neoplasias/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Lysosomes play a key role in regulating cell death in response to cancer therapies, yet little is known on the possible role of lysosomes in the therapeutic efficacy of G-quadruplex DNA ligands (G4L) in cancer cells. Here, we investigate the relationship between the modulation of lysosomal membrane damage and the degree to which cancer cells respond to the cytotoxic effects of G-quadruplex ligands belonging to the triarylpyridine family. Our results reveal that the lead compound of this family, 20A promotes the enlargement of the lysosome compartment as well as the induction of lysosome-relevant mRNAs. Interestingly, the combination of 20A and chloroquine (an inhibitor of lysosomal functions) led to a significant induction of lysosomal membrane permeabilization coupled to massive cell death. Similar effects were observed when chloroquine was added to three new triarylpyridine derivatives. Our findings thus uncover the lysosomal effects of triarylpyridines compounds and delineate a rationale for combining these compounds with chloroquine to increase their anticancer effects.
RESUMO
G-quadruplex (G4) ligands have shown anti-tumor activity by stabilizing G4 structures. We recently reported that the G4 ligand 20A promotes senescence in cancer cells through Ataxia Telangiectasia Mutated (ATM) and autophagy activation. Inhibition of both pathways directs cells to apoptosis, positioning ATM/autophagy axis as a linchpin between senescence and apoptosis.