BACKGROUND Colorectal cancer (CRC) is the third most prevalent malignancy and has the fourth highest global cancer mortality rate. Early diagnosis and prompt medical attention can improve quality of life and the prognosis of CRC patients. Accumulating evidence reveals that long non-coding RNAs (lncRNAs) function as oncogenes or anti-oncogenes, as well as biomarkers in various cancers. AIM To investigate the levels and molecular mechanism of the lncRNA maternally expressed gene 3 (MEG3) in CRC. METHODS The levels of lncRNA MEG3 in CRC tissue, serum and cell line samples were explored via qRT-PCR. The relationship between MEG3 levels and clinicopathological features in CRC was investigated. The diagnostic and prognostic values of serum MEG3 levels were analyzed with ROC curves and Kaplan‑Meier survival curves, respectively. RESULTS Significant decreased levels of MEG3 existed in CRC tissue, cell lines and serum. CRC patients with down-regulated serum MEG3 levels had larger tumor sizes, and advanced clinical stages. The sensitivity and specificity of serum MEG3 levels in CRC detection was 0.667 and 0.875, respectively. Tumor size, T stages, and serum MEG3 levels are indie factors that produce an effect on CRC patients' prognosis. Kaplan‑Meier survival curves suggested that CRC patients with high levels of MEG3 had a remarkably better overall survival rate. CONCLUSION LncRNA MEG3 is down-regulated in CRC, and regulates cell functions by targeting adenosine deaminase’s effect on RNA 1 in CRC.

Piezocatalytic therapy is a new-emerging reactive oxygen species (ROS)-enabled therapeutic strategy that relies on built-in electric field and energy-band bending of piezoelectric materials activated by ultrasound (US) irradiation. Despite becoming a hot topic, material development and mechanism exploration are still underway. Herein, as-synthesized oxygen-vacancy-rich BiO 2−x nanosheets (NSs) demonstrate outstanding piezoelectric properties. Under US, a piezo-potential of 0.25 V for BiO 2−x NSs is sufficient to tilt the conduction band to be more negative than the redox potentials of O 2 / • O 2 − , • O 2 − /H 2 O 2 , and H 2 O 2 / • OH, which initiates a cascade reaction for ROS generation. Moreover, the BiO 2−x NSs exhibit peroxidase and oxidase-like activities to augment ROS production, especially in the H 2 O 2 -overexpressed tumor microenvironment. Density functional theory calculations show that the generated oxygen vacancies in BiO 2−x NSs are favorable for H 2 O 2 adsorption and increasing the carrier density to produce ROS. Furthermore, the quick movement of electrons enables an excellent sonothermal effect, for example, rapid rise in temperature to nearly 65 °C upon US with low power (1.2 W cm −2 ) and short time (96 s). Therefore, this system realizes a multimode synergistic combination of piezocatalytic, enzymatic, and sonothermal therapies, providing a new direction for defect engineering-optimized piezoelectric materials for tumor therapy.

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