N6-Methyladenosine Reader YTHDF1 Promotes ARHGEF2 Translation and RhoA Signaling in Colorectal Cancer.

BACKGROUND & AIMS: N6-methyladenosine (m6A) governs the fate of RNAs through m6A readers. Colorectal cancer (CRC) exhibits aberrant m6A modifications and expression of m6A regulators. However, how m6A readers interpret oncogenic m6A methylome to promote malignant transformation remains to be illustrated. METHODS: YTH N6-methyladenosine RNA binding protein 1 (Ythdf1) knockout mouse was generated to determine the effect of Ythdf1 in CRC tumorigenesis in vivo. Multiomic analysis of RNA-sequencing, m6A methylated RNA immunoprecipitation sequencing, YTHDF1 RNA immunoprecipitation sequencing, and proteomics were performed to unravel targets of YTHDF1 in CRC. The therapeutic potential of targeting YTHDF1-m6A-Rho/Rac guanine nucleotide exchange factor 2 (ARHGEF2) was evaluated using small interfering RNA (siRNA) encapsulated by lipid nanoparticles (LNP). RESULTS: DNA copy number gain of YTHDF1 is a frequent event in CRC and contributes to its overexpression. High expression of YTHDF1 is significantly associated with metastatic gene signature in patient tumors. Ythdf1 knockout in mice dampened tumor growth in an inflammatory CRC model. YTHDF1 promotes cell growth in CRC cell lines and primary organoids and lung and liver metastasis in vivo. Integrative multiomics analysis identified RhoA activator ARHGEF2 as a key downstream target of YTHDF1. YTHDF1 binds to m6A sites of ARHGEF2 messenger RNA, resulting in enhanced translation of ARHGEF2. Ectopic expression of ARHGEF2 restored impaired RhoA signaling, cell growth, and metastatic ability both in vitro and in vivo caused by YTHDF1 loss, verifying that ARHGEF2 is a key target of YTHDF1. Finally, ARHGEF2 siRNA delivered by LNP significantly suppressed tumor growth and metastasis in vivo. CONCLUSIONS: We identify a novel oncogenic epitranscriptome axis of YTHDF1-m6A-ARHGEF2, which regulates CRC tumorigenesis and metastasis. siRNA-delivering LNP drug validated the therapeutic potential of targeting this axis in CRC.

Nanostructure-Driven Indocyanine Green Dimerization Generates Ultra-Stable Phototheranostics Nanoparticles.

Indocyanine green (ICG) is the only near-infrared (NIR) dye approved for clinical use. Despite its versatility in photonic applications and potential for photothermal therapy, its photobleaching hinders its application. Here we discovered a nanostructure of dimeric ICG (Nano-dICG) generated by using ICG to stabilize nanoemulsions, after which ICG enabled complete dimerization on the nanoemulsion shell, followed by J-aggregation of ICG-dimer, resulting in a narrow, red-shifted (780 nm→894 nm) and intense (≈2-fold) absorbance. Compared to ICG, Nano-dICG demonstrated superior photothermal conversion (2-fold higher), significantly reduced photodegradation (-9.6 % vs. -46.3 %), and undiminished photothermal effect (7 vs. 2 cycles) under repeated irradiations, in addition to excellent colloidal and structural stabilities. Following intravenous injection, Nano-dICG enabled real-time tracking of its delivery to mouse tumors within 24 h by photoacoustic imaging at NIR wavelength (890 nm) distinct from the endogenous signal to guide effective photothermal therapy. The unprecedented finding of nanostructure-driven ICG dimerization leads to an ultra-stable phototheranostic platform.

Redox-Activated Porphyrin-Based Liposome Remote-Loaded with Indoleamine 2,3-Dioxygenase (IDO) Inhibitor for Synergistic Photoimmunotherapy through Induction of Immunogenic Cell Death and Blockage of IDO Pathway.

Immunotherapy through stimulating the host immune system has emerged as a powerful therapeutic strategy for various malignant and metastatic tumors in the clinic. However, harnessing the immune system for cancer treatment often fails to obtain a durable response rate due to the poor immunogenicity and the strong immunosuppressive milieu in the tumor site. Herein, a redox-activated liposome was developed from the self-assembly of the porphyrin-phospholipid conjugate and coencapsulation of indoleamine 2,3-dioxygenase (IDO) inhibitor into the interior lumen via remote-loading for simultaneous induction of immunogenic cell death (ICD) and reversing of suppressive tumor microenvironment. The nanoparticle exhibited prolonged blood circulation and enhanced tumor accumulation in the 4T1 tumor-bearing mice after intravenous injection. The nanovesicle could render exponential activation of fluorescence signal and photodynamic therapy (PDT) activity (>100-fold) in response to the high level of intracellular glutathione after endocytosed by tumor cells, thereby achieving effective inhibition of tumor growth and reduced phototoxicity to normal tissues owing to the activatable design of the nanoparticle. More importantly, redox-activated PDT induced intratumoral infiltration of cytotoxic T lymphocytes by induction of ICD of tumor cells. After combining with the IDO inhibitor, the systemic antitumor immune response was further augmented. Hence, we believe that the present nanovesicle strategy has the potential for the synergistic immunotherapy of the metastatic cancers.

Novel nano-encapsulated limonene: Utilization of drug-in-cyclodextrin-in-liposome formulation to improve the stability and enhance the antioxidant activity.

Drug-in-cyclodextrin-in-liposome (DCL) combines advantages of cyclodextrin and liposome. Here, DCL formulation was successfully prepared to encapsulate limonene (Lim), whose characterization revealed that particle size was 147.5 ± 1.3 nm and zeta potential was -48.7 ± 0.8 mV. And the complexation mechanism of Lim/HP-ß-CD inclusion complex (the intermediate of DCL) was analyzed by molecular dynamics simulation, showing that Lim was entrapped into the cavity of HP-ß-CD through electrostatic and hydrophobic interaction with a molar ratio of 1:1. Notably, DCL formulation not only reduced Lim volatilization in 25℃, but also enhanced the free radical (DPPH· and ABTS·+) scavenging ability of Lim. In summary, Lim-DCL formulation improved the stability and enhanced the antioxidant activity of Lim. DCL nanocarrier system is suitable to preserve volatile and hydrophobic compounds, enlarging their application in pharmaceutics industries.