RESUMEN
Streptococcus anginosus (S. anginosus) was enriched in the gastric mucosa of patients with gastric cancer (GC). Here, we show that S. anginosus colonized the mouse stomach and induced acute gastritis. S. anginosus infection spontaneously induced progressive chronic gastritis, parietal cell atrophy, mucinous metaplasia, and dysplasia in conventional mice, and the findings were confirmed in germ-free mice. In addition, S. anginosus accelerated GC progression in carcinogen-induced gastric tumorigenesis and YTN16 GC cell allografts. Consistently, S. anginosus disrupted gastric barrier function, promoted cell proliferation, and inhibited apoptosis. Mechanistically, we identified an S. anginosus surface protein, TMPC, that interacts with Annexin A2 (ANXA2) receptor on gastric epithelial cells. Interaction of TMPC with ANXA2 mediated attachment and colonization of S. anginosus and induced mitogen-activated protein kinase (MAPK) activation. ANXA2 knockout abrogated the induction of MAPK by S. anginosus. Thus, this study reveals S. anginosus as a pathogen that promotes gastric tumorigenesis via direct interactions with gastric epithelial cells in the TMPC-ANXA2-MAPK axis.
Asunto(s)
Gastritis , Neoplasias Gástricas , Infecciones Estreptocócicas , Streptococcus anginosus , Animales , Humanos , Ratones , Atrofia/patología , Carcinogénesis , Transformación Celular Neoplásica , Mucosa Gástrica , Gastritis/patología , Inflamación/patología , Proteínas Quinasas Activadas por Mitógenos , Neoplasias Gástricas/microbiología , Neoplasias Gástricas/patología , Streptococcus anginosus/fisiología , Infecciones Estreptocócicas/patologíaRESUMEN
Peptostreptococcus stomatis (P. stomatis) is enriched in colorectal cancer (CRC), but its causality and translational implications in CRC are unknown. Here, we show that P. stomatis accelerates colonic tumorigenesis in ApcMin/+ and azoxymethane/dextran sodium sulfate (AOM-DSS) models by inducing cell proliferation, suppressing apoptosis, and impairing gut barrier function. P. stomatis adheres to CRC cells through its surface protein fructose-1,6-bisphosphate aldolase (FBA) that binds to the integrin α6/ß4 receptor on CRC cells, leading to the activation of ERBB2 and the downstream MEK-ERK-p90 cascade. Blockade of the FBA-integrin α6/ß4 abolishes ERBB2-mitogen-activated protein kinase (MAPK) activation and the protumorigenic effect of P. stomatis. P. stomatis-driven ERBB2 activation bypasses receptor tyrosine kinase (RTK) blockade by EGFR inhibitors (cetuximab, erlotinib), leading to drug resistance in xenograft and spontaneous CRC models of KRAS-wild-type CRC. P. stomatis also abrogates BRAF inhibitor (vemurafenib) efficacy in BRAFV600E-mutant CRC xenografts. Thus, we identify P. stomatis as an oncogenic bacterium and a contributory factor for non-responsiveness to RTK inhibitors in CRC.
Asunto(s)
Carcinogénesis , Neoplasias Colorrectales , Resistencia a Antineoplásicos , Peptostreptococcus , Receptor ErbB-2 , Animales , Humanos , Ratones , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/microbiología , Neoplasias Colorrectales/patología , Fructosa-Bifosfato Aldolasa/metabolismo , Fructosa-Bifosfato Aldolasa/genética , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteínas Quinasas Activadas por Mitógenos/genética , Receptor ErbB-2/metabolismo , Receptor ErbB-2/genética , /farmacologíaRESUMEN
The N6-methyladenosine (m6A) RNA binding protein YTHDF1 is frequently overexpressed in colorectal cancer (CRC) and drives chemotherapeutic resistance. To systematically identify druggable targets in CRC with high expression of YTHDF1, we employed a CRISPR/Cas9 screening strategy that revealed RUVBL1 and RUVBL2 as putative targets.RUVBL1/2 were overexpressed in primary CRC samples and represented independent predictors of poor patient prognosis. Functionally, loss of RUVBL1/2 preferentially impaired the growth ofYTHDF1-high CRC cells, patient-derived primary CRC organoids, and subcutaneous xenografts. Mechanistically, YTHFD1 and RUVBL1/2 formed a positive feed-forward circuit to accelerate oncogenic translation. YTHDF1 bound to m6A-modified RUVBL1/2 mRNA to promote translation initiation and protein expression. Co-IP and mass spectrometry identified that RUVBL1/2 reciprocally interacted with YTHDF1 at 40S translation initiation complexes. Consequently, RUVBL1/2 depletion stalled YTHDF1-driven oncogenic translation and nascent protein biosynthesis, leading to proliferative arrest and apoptosis. Ribo-seq revealed that RUVBL1/2 loss impaired the activation of MAPK, RAS and PI3K-AKT signaling induced by YTHDF1. Finally, blockade of RUVBL1/2 by the pharmacological inhibitor CB6644 or vesicle-like nanoparticle-encapsulated siRNAs preferentially arrested the growth of YTHDF1-expressing CRC in vitro and in vivo. Together, this study uncovered that RUVBL1/2 are potential prognostic markers and druggable targets that regulate protein translation in YTHDF1-high CRC.
RESUMEN
KRAS is an important tumor intrinsic factor driving immune suppression in colorectal cancer (CRC). In this study, we demonstrate that SLC25A22 underlies mutant KRAS-induced immune suppression in CRC. In immunocompetent male mice and humanized male mice models, SLC25A22 knockout inhibits KRAS-mutant CRC tumor growth with reduced myeloid derived suppressor cells (MDSC) but increased CD8+ T-cells, implying the reversion of mutant KRAS-driven immunosuppression. Mechanistically, we find that SLC25A22 plays a central role in promoting asparagine, which binds and activates SRC phosphorylation. Asparagine-mediated SRC promotes ERK/ETS2 signaling, which drives CXCL1 transcription. Secreted CXCL1 functions as a chemoattractant for MDSC via CXCR2, leading to an immunosuppressive microenvironment. Targeting SLC25A22 or asparagine impairs KRAS-induced MDSC infiltration in CRC. Finally, we demonstrate that the targeting of SLC25A22 in combination with anti-PD1 therapy synergizes to inhibit MDSC and activate CD8+ T cells to suppress KRAS-mutant CRC growth in vivo. We thus identify a metabolic pathway that drives immunosuppression in KRAS-mutant CRC.
Asunto(s)
Linfocitos T CD8-positivos , Neoplasias Colorrectales , Masculino , Ratones , Animales , Línea Celular Tumoral , Linfocitos T CD8-positivos/metabolismo , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Neoplasias Colorrectales/terapia , Neoplasias Colorrectales/tratamiento farmacológico , Asparagina , Inmunoterapia , Microambiente TumoralRESUMEN
OBJECTIVE: To investigate the role of miR- 433 in chemoresistance to docetaxel in breast cancer cells. METHODS: A docetaxel-resistant MCF-7 breast cancer cell line (MCF-7/DOX) was established by exposure of parental MCF-7 cells to progressively increased docetaxel concentrations. The functional role of miR-433 was investigated by assessing the changes in viability and apoptosis of the cells transfected with a miR-433 inhibitor or a miR-433 mimics. The downstream targets of miR- 433 were determined by bioinformatics analysis, cell transfection and luciferase reporter assay. RESULTS: Quantitative real-time PCR analysis showed that miR- 433 was down-regulated in MCF-7/DOX cells. Transfection of the cells with the miR-433 inhibitor obviously enhanced chemoresistance to docetaxel and attenuated cell apoptosis in MCF-7 cells; miR-433 overexpression significantly increased the sensitivity to docetaxel and promoted apoptosis in MCF- 7/DOX cells. Luciferase reporter assay showed that the down-regulation miR-433 expression was associated with significantly increased expressions of Notch1 at both mRNA and protein levels in MCF-7 cells. Compared with the control cells, McF-7/DOX cells transfected with miR-433 mimics exhibited significantly decreased mRNA and protein expressions of Notch1. CONCLUSIONS: miR-433 may reverse chemoresistance to docetaxel by targeting Notch1 in breast cancer cells.