RESUMEN
Neutrophil extracellular traps (NETs), a web-like structure of cytosolic and granule proteins assembled on decondensed chromatin, kill pathogens and cause tissue damage in diseases. Whether NETs can kill cancer cells is unexplored. Here, we report that a combination of glutaminase inhibitor CB-839 and 5-FU inhibited the growth of PIK3CA-mutant colorectal cancers (CRCs) in xenograft, syngeneic, and genetically engineered mouse models in part through NETs. Disruption of NETs by either DNase I treatment or depletion of neutrophils in CRCs attenuated the efficacy of the drug combination. Moreover, NETs were present in tumor biopsies from patients treated with the drug combination in a phase II clinical trial. Increased NET levels in tumors were associated with longer progression-free survival. Mechanistically, the drug combination induced the expression of IL-8 preferentially in PIK3CA-mutant CRCs to attract neutrophils into the tumors. Further, the drug combination increased the levels of ROS in neutrophils, thereby inducing NETs. Cathepsin G (CTSG), a serine protease localized in NETs, entered CRC cells through the RAGE cell surface protein. The internalized CTSG cleaved 14-3-3 proteins, released BAX, and triggered apoptosis in CRC cells. Thus, our studies illuminate a previously unrecognized mechanism by which chemotherapy-induced NETs kill cancer cells.
Asunto(s)
Neoplasias Colorrectales , Trampas Extracelulares , Humanos , Animales , Ratones , Modelos Animales de Enfermedad , Fosfatidilinositol 3-Quinasa Clase I , Combinación de Medicamentos , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genéticaRESUMEN
Noonan syndrome (NS) is a developmental syndrome caused by germline mutations in the Ras signaling pathway. No association has been shown between NS and pediatric colorectal cancer (CRC). We report the case of CRC in a pediatric patient with NS. The patient underwent whole genome sequencing. A germline SOS1 mutation c.1310T>C (p. Ile437Thr) confirmed NS diagnosis. No known hereditary cancer syndromes were identified. Tumor analysis revealed two mutations: a TP53 missense mutation c.481G>A (p. Ala161Tyr) and NCOR1 nonsense mutation c.6052C>T (p. Arg2018*). This report highlights the complexity of Ras signaling and the interplay between developmental syndromes and cancer.
Asunto(s)
Neoplasias Colorrectales/complicaciones , Neoplasias Colorrectales/genética , Síndrome de Noonan/complicaciones , Síndrome de Noonan/genética , Adolescente , Femenino , Estudio de Asociación del Genoma Completo , Mutación de Línea Germinal , Humanos , Co-Represor 1 de Receptor Nuclear/genética , Proteína SOS1/genética , Proteína p53 Supresora de Tumor/genéticaRESUMEN
TRPM2 is a Ca2+-permeable, nonselective cation channel that plays a role in oxidant-induced cell death, insulin secretion, and cytokine release. Few TRPM2 inhibitors have been reported, which hampers the validation of TRPM2 as a drug target. While screening our in-house marine-derived chemical library, we identified scalaradial and 12-deacetylscalaradial as the active components within an extract of an undescribed species of Cacospongia (class Demospongiae, family Thorectidae) that strongly inhibited TRPM2-mediated Ca2+ influx in TRPM2-overexpressing HEK293 cells. In whole-cell patch-clamp experiments, scalaradial (and similarly 12-deacetylscalaradial) inhibited TRPM2-mediated currents in a concentration- and time-dependent manner (â¼20 min to full onset; IC50 210 nM). Scalaradial inhibited TRPM7 with less potency (IC50 760 nM) but failed to inhibit CRAC, TRPM4, and TRPV1 currents in whole-cell patch clamp experiments. Scalaradial's effect on TRPM2 channels was shown to be independent of its well-known ability to inhibit secreted phospholipase A2 (sPLA2) and its reported effects on extracellular signal-regulated kinases (ERK) and Akt pathways. In addition, scalaradial was shown to inhibit endogenous TRPM2 currents in a rat insulinoma cell line (IC50 330 nM). Based on its potency and emerging specificity profile, scalaradial is an important addition to the small number of known TRPM2 inhibitors.
Asunto(s)
Homoesteroides/farmacología , Sesterterpenos/farmacología , Canales Catiónicos TRPM/antagonistas & inhibidores , Animales , Calcio/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/efectos de los fármacos , Homoesteroides/química , Humanos , Estructura Molecular , Fosfolipasas A2/efectos de los fármacos , Ratas , Sesterterpenos/químicaRESUMEN
Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) play a role in both innate immunity as well as cellular injury. H2O2 induces changes in intracellular calcium ([Ca(2+)]i) in many cell types and this seems to be at least partially mediated by transient receptor potential melastatin 2 (TRPM2) in cells that express this channel. Here we show that low concentrations of H2O2 induce the activation of the Ca(2+)-release activated Ca(2+) current I(CRAC). This effect is not mediated by direct CRAC channel activation, since H2O2 does not activate heterologously expressed CRAC channels independently of stromal interaction molecule (STIM). Instead, I(CRAC) activation is partially mediated by store depletion through activation of inositol 1,4,5 trisphosphate receptors (IP3R), since pharmacological inhibition of IP3 receptors by heparin or molecular knock-out of all IP3 receptors in DT40 B cells strongly reduce H2O2-induced I(CRAC). The remainder of H2O2-induced I(CRAC) activation is likely mediated by IP3R-independent store-depletion. Our data suggest that H2O2 can activate Ca(2+) entry through TRPM2 as well as store-operated CRAC channels, thereby adding a new facet to ROS-induced Ca(2+) signaling.