RESUMO
N-methyladenosine (m6A) represents a prevalent RNA modification observed in colorectal cancer. Despite its abundance, the biological implications of m6A methylation on the lncRNA CARMN remain elusive in colorectal cancer, especially for mutant p53 gain-of-function. Here, we elucidate that CARMN exhibits diminished expression levels in colorectal cancer patients with mutant p53, attributed to its rich m6A methylation, which promotes cancer proliferation, invasion and metastasis in vitro and in vivo. Further investigation illustrates that ALKBH5 acts as a direct demethylase of CARMN, targeting 477 methylation sites, thereby preserving CARMN expression. However, the interaction of mutant p53 with the ALKBH5 promoter impedes its transcription, enhancing m6A methylation levels on CARMN. Subsequently, YTHDF2/YTHDF3 recognise and degrade m6A-modified CARMN. Concurrently, overexpressing CARMN significantly suppressed colorectal cancer progression in vitro and in vivo. Additionally, miR-5683 was identified as a direct downstream target of lncRNA CARMN, exerting an antitumour effect by cooperatively downregulating FGF2 expression. Our findings revealed the regulator and functional mechanism of CARMN in colorectal cancer with mutant p53, potentially offering insights into demethylation-based strategies for cancer diagnosis and therapy. The m6A methylation of CARMN that is prime for mutant p53 gain-of-function-induced malignant progression of colorectal cancer, identifying a promising approach for cancer therapy.
Assuntos
Homólogo AlkB 5 da RNA Desmetilase , Neoplasias Colorretais , MicroRNAs , RNA Longo não Codificante , Proteína Supressora de Tumor p53 , Humanos , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Homólogo AlkB 5 da RNA Desmetilase/genética , Homólogo AlkB 5 da RNA Desmetilase/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Proteína Supressora de Tumor p53/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Neoplasias Colorretais/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Animais , Camundongos , Progressão da Doença , Desmetilação , Linhagem Celular Tumoral , Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/genética , Camundongos Nus , Regulação Neoplásica da Expressão GênicaRESUMO
Ferroptosis is a new type of iron-dependent programmed cell death induced by lipid peroxidation. However, the underlying mechanisms and function in tumor therapy still remain undisclosed especially in post-transcription regulation. Here, we found that targeting AKT significantly induced GPX4 dependent ferroptosis and suppressed colorectal cancer growth both in vitro and in vivo. During this process, demethylase FTO was downregulated, which increased the m6A methylation level of GPX4, subsequently recognized by YTHDF2 and degraded. Prediction results showed that there are three potential methylated sites (193/647/766), and 193 site was identified as the right one, which was demethylated by FTO and read by YTHDF2. In parallel, AKT inhibition caused the accumulation of ROS which had a negative feedback on GPX4 expression. In addition, protective autophagy was initiated by MK2206 stimulation, while blocking autophagy further increased ferroptosis and markedly enhanced the anti-tumor activity of MK2206. In a word, inhibiting AKT activated ferroptosis through FTO/YTHDF2/GPX4 axis to suppress colon cancer progression, which raised FTO/GPX4 as potential biomarkers and targets in colorectal cancer therapy.