RESUMO
Actin cytoskeleton dynamic rearrangement is required for tumor cell metastasis and is a key characteristic of Helicobacter pylori (H. pylori)-infected host cells. Actin cytoskeleton modulation is coordinated by multiple actin-binding proteins (ABP). Through Kyoto encyclopedia of gene and genomes database, GEPIA website, and real-time PCR data, we found that H. pylori infection significantly induced L-plastin, a key ABP, in gastric cancer cells. We further explored the regulation and function of L-plastin in H. pylori-associated gastric cancer and found that, mechanistically, H. pylori infection induced gastric cancer cells to express L-plastin via cagA-activated ERK signaling pathway to mediate SP1 binding to L-plastin promoter. Moreover, this increased L-plastin promoted gastric cancer cell proliferation and migration in vitro and facilitated the growth and metastasis of gastric cancer in vivo. Finally, we detected the expression pattern of L-plastin in gastric cancer tissues, and found that L-plastin was increased in gastric cancer tissues and that this increase of L-plastin positively correlated with cagA + H. pylori infection status. Overall, our results elucidate a novel mechanism of L-plastin expression induced by H. pylori, and a new function of L-plastin-facilitated growth and metastasis of gastric cancer, and thereby implicating L-plastin as a potential therapeutic target against gastric cancer. IMPLICATIONS: Our results elucidate a novel mechanism of L-plastin expression induced by H. pylori in gastric cancer, and a new function of L-plastin-facilitated gastric cancer growth and metastasis, implicating L-plastin as a potential therapeutic target against gastric cancer.
Assuntos
Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Infecções por Helicobacter/genética , Helicobacter pylori/genética , Sistema de Sinalização das MAP Quinases/genética , Glicoproteínas de Membrana/genética , Proteínas dos Microfilamentos/genética , Fator de Transcrição Sp1/genética , Neoplasias Gástricas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Antígenos de Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Infecções por Helicobacter/metabolismo , Infecções por Helicobacter/microbiologia , Helicobacter pylori/fisiologia , Humanos , Masculino , Glicoproteínas de Membrana/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Nus , Proteínas dos Microfilamentos/metabolismo , Pessoa de Meia-Idade , Metástase Neoplásica , Fator de Transcrição Sp1/metabolismo , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/microbiologia , Transplante HeterólogoRESUMO
Myeloid-derived suppressor cells (MDSCs) are a prominent component of the pro-tumoral response. The phenotype of and mechanisms used by MDSCs is heterogeneous and requires more precise characterization in gastric cancer (GC) patients. Here, we have identified a novel subset of CD45+CD33lowCD11bdim MDSCs in the peripheral blood of GC patients compared to healthy individuals. CD45+CD33lowCD11bdim MDSCs morphologically resembled neutrophils and expressed high levels of the neutrophil marker CD66b. Circulating CD45+CD33lowCD11bdim MDSCs effectively suppressed CD8+ T cells activity through the inhibition of CD8+ T cell proliferation and interferon-γ (IFN-γ) and granzyme B (GrB) production. The proportion of CD45+CD33lowCD11bdim MDSCs also negatively correlated with the proportion of IFN-γ+CD8+ T cell in the peripheral blood of GC patients. GC patient serum-derived IL-6 and IL-8 activated and induced CD45+CD33lowCD11bdim MDSCs to express arginase I via the PI3K-AKT signaling pathway. This pathway contributed to CD8+ T cell suppression as it was partially rescued by the blockade of the IL-6/IL-8-arginase I axis. Peripheral blood CD45+CD33lowCD11bdim MDSCs, as well as IL-6, IL-8, and arginase I serum levels, positively correlated with GC progression and negatively correlated with overall patient survival. Altogether, our results highlight that a subset of neutrophilic CD45+CD33lowCD11bdim MDSCs is functionally immunosuppressive and activated via the IL-6/IL-8-arginase I axis in GC patients.
