RESUMO
Colorectal cancer (CRC) is a leading cause of cancer death worldwide and about 20% is metastatic at diagnosis and untreatable. The anti-EGFR therapy in metastatic patients is led by the presence of KRAS-mutations in tumor tissue. KRAS-wild-type CRC patients showed a positive response rate of about 70% to cetuximab or panitumumab combined with chemotherapy. MiRNAs are promising markers in oncology and could improve our knowledge on pathogenesis and drug resistance in CRC patients. This class of molecules represents an opportunity for the development of miRNA-based strategies to overcome the ineffectiveness of anti-EGFR therapy. We performed an integrative analysis of miRNA expression profile between KRAS-mutated CRC and KRAS-wildtype CRC and paired normal colic tissue (NCT). We revealed an overexpression of miR-425-5p in KRAS-mutated CRC compared to KRAS-wild type CRC and NCT and demonstrated that miR-425-5p exerts regulatory effects on target genes involved in cellular proliferation, migration, invasion, apoptosis molecular networks. These epigenetic mechanisms could be responsible of the strong aggressiveness of KRAS-mutated CRC compared to KRAS-wildtype CRC. We proved that some miR-425-5p targeted genes are involved in EGFR tyrosine kinase inhibitor resistance pathway, suggesting that therapies based on miR-425-5p may have strong potential in targeting KRAS-driven CRC. Moreover, we demonstrated a role in the oncogenesis of miR-31-5p, miR-625-5p and miR-579 by comparing CRC versus NCT. Our results underlined that miR-425-5p might act as an oncogene to participate in the pathogenesis of KRAS-mutated CRC and contribute to increase the aggressiveness of this subcategory of CRC, controlling a complex molecular network.
Assuntos
Neoplasias Colorretais/genética , Epigênese Genética/genética , MicroRNAs/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Apoptose/efeitos dos fármacos , Carcinogênese/efeitos dos fármacos , Carcinogênese/genética , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cetuximab/administração & dosagem , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Mutação/genética , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Proteínas de Neoplasias/genética , Panitumumabe/administração & dosagem , Inibidores de Proteínas Quinases/administração & dosagem , Proteínas Proto-Oncogênicas B-raf/genéticaRESUMO
Colorectal cancer (CRC) ranks as the most frequent carcinoma worldwide. CRC patients show strong prognostic differences and responses to treatment, and 20% have incurable metastatic disease at diagnosis. We considered it essential to investigate mechanisms that control cellular regulatory networks, such as the miRNA-mRNA interaction, known to be involved in cancer pathogenesis. We conducted a human miRNome analysis by TaqMan low density array, comparing CRC to normal colon tissue (NCT, and experimentally identified gene targets of miRNAs deregulated, by anti-correlation analysis, with the CRC whole-transcriptome profile obtained from RNASeq experiments. We identified an integrated signature of 20 deregulated miRNAs in CRC. Enrichment analyses of the gene targets controlled by these miRNAs brought to light 25 genes, members of pathways known to lead to cell growth and death (CCND1, NKD1, FZD3, MAD2L1, etc.), such as cell metabolism (ACSL6, PRPS1-2). A screening of prognosis-mediated miRNAs underlined that the overexpression of miR-224 promotes CRC metastasis, and is associated with high stage and poor survival. These findings suggest that the biology and progression of CRC depend on deregulation of multiple miRNAs that cause a complex dysfunction of cellular molecular networks. Our results have further established miRNA-mRNA interactions and defined multiple pathways involved in CRC pathogenesis.
