Background: N⁶-Methyladenosine (m⁶A) modification has been implicated in many biological processes. It is important for the regulation of messenger RNA (mRNA) stability, splicing, and translation. However, its role in cancer has not been studied in detail. Here we investigated the biological role and underlying mechanism of m⁶A modification in hepatoblastoma (HB). Methods: We used Reverse transcription quantitative real-time PCR (RT-qPCR) and Western blotting to determine the expression of m⁶A related factors. And we clarified the effects of these factors on HB cells using cell proliferation assay, colony formation, apoptotic assay. Then we investigated of methyltransferase-like 13 (METTL3) and its correlation with clinicopathological features and used xenograft experiment to check METTL3 effect in vivo. m⁶A-Seq was used to profiled m⁶A transcriptome-wide in hepatoblastoma tumor tissue and normal tissue. Finally, methylated RNA immunoprecipitation (MeRIP) assay, RNA remaining assay to perform the regulator mechanism of MEETL3 on the target CTNNB1 in HB. Results: In this research, we discovered that m⁶A modifications are increased in hepatoblastoma, and METTL3 is the main factor involved with aberrant m⁶A modification. We also profiled m⁶A across the whole transcriptome in hepatoblastoma tumor tissues and normal tissues. Our findings suggest that m⁶A is highly expressed in hepatoblastoma tumors. Also, m⁶A is enriched not only around the stop codon, but also around the coding sequence (CDS) region. Gene ontology analysis indicates that m⁶A mRNA methylation contributes significantly to regulate the Wnt/β-catenin pathway. Reduced m⁶A methylation can lead to a decrease in expression and stability of the CTNNB1. Conclusion: Overall our findings suggest enhanced m⁶A mRNA methylation as an oncogenic mechanism in hepatoblastoma, METTL3 is significantly up-regulated in HB and promotes HB development. And identify CTNNB1 as a regulator of METTL3 guided m⁶A modification in HB.

Polypyridine Ru(II) complexes have long been deemed to excellent antitumor agents that inhibit the proliferation of breast cancer cells. Nevertheless, their effects on the metastatic potency of breast cancer cells need further research. Herein, a class of polypyridine Ru(II) complexes coordinated with phenazine derivates (DPPZ) ([Ru(bpy)₂(DPPZ-R)](ClO₄)₂, Ru(bpy) ₂ DPPZ: R = -H, Ru(bpy) ₂ BrDPPZ: R = -Br, Ru(bpy) ₂ MDPPZ: R = -CH₃, Ru(bpy)2BnDPPZ: R = -acene, Ru(bpy) ₂ BEDPPZ: R = -C ≡ C(C₆H₅)) was synthesized by introducing different substituent groups to regulate the electron cloud density and planarity of the main ligands. Results indicated that this class of DPPZ-based Ru(II) complexes exhibited promising inhibitory effect against MDA-MB-231 triple-negative breast cancer cells, especially for Ru(bpy) ₂ BEDPPZ, which is comparable with that of cisplatin. In addition, Ru(bpy) ₂ BEDPPZ effectively inhibited the migration and invasion of MDA-MB-231 cells in vitro and suppressed focal adhesion and stress fiber formation. Moreover, it effectively blocked MDA-MB-231 cell metastasis in blood vessels and restrained angiogenesis formation in a zebrafish xenograft breast cancer model. Further studies showed that the mechanisms may involve DNA damage-mediated apoptosis probably due to Ru(bpy) ₂ BEDPPZ, which was enriched in the cell nucleus and induced DNA damage. All these results suggested that the DPPZ-based Ru(II) complexes can act as potent anti-metastasis agents.

This study aimed to synthesize two ruthenium(II) complexes modified with aryl alkynes [Ru(phen)₂(TMSEPIP)](ClO₄)₂ (1, phen = 1,10-phenanthrolin; TMSEPIP = 2-(2-trimethylsilylethylphenyl)imidazole[4,5f][1,10] phenanthroline) and [Ru(phen)₂(BEPIP)](ClO₄)₂ (2, BEPIP = 2-(2-phenethylphenyl)imidazole[4,5f][1,10]phenanthroline) and evaluate their ability to act as luminescent probes of c-myc G-quadruplex DNA. It was discovered that the luminescence of 1 decreased in the presence of c-myc G-quadruplex DNA, while the luminescence of 2 clearly increased under the same conditions. Besides, in the presence of double-stranded DNA, the luminescence intensity of 1 and 2 showed little obvious change. It was interesting to find by atomic force microscopy that 1 could promote c-myc G-quadruplex DNA self-assembly to form a nano-network structure, while 2 could promote the formation of a nanowire structure. Further studies showed that 1 was inserted into the groove formed by base pairs A6-G8 and G21-T23 of c-myc G-quadruplex DNA, while 2 was inserted into the groove formed by G7-G9 and G22-A24. It is speculated that 2 can be developed as a potential luminescent switch-on probe through selectively recognizing and promoting self-assembly of c-myc G-quadruplex DNA.

A series of polypyridyl ruthenium(II) complexes coordinated by phenanthroimidazole derivatives [Ru(phen)₂(R)](ClO₄)₂ (where 1 R = IP, 2 R = PIP, 3 R = p-HPIP, 4 R = p-OCH₃PIP) was synthesized with an average yield of >85% under microwave irradiation at 140 °C for 30 min. The inhibitory effect of these complexes against various tumour cells were evaluated by MTT assay, and the results showed that these polypyridyl ruthenium(II) complexes exhibited acceptable inhibition against different tumour cells, especially 4, with an IC₅₀ of 18.4 μM for Hela cells. The results showed that 4 inhibited the growth of cervical cancer Hela cells by inducing G2/M phase arrest, which was followed by slight apoptosis. Further studies showed that 4 displayed better inhibition against the invasion and metastasis of Hela cells than NAMI-A. Studies on the in vivo distribution and metabolism indicated that 4 was rapidly distributed in the entire body, absorbed by the tumour tissue and had only a small accumulation of toxicity in the body. These results demonstrated that this type of ruthenium(II) complex can block the growth of Hela cells and inhibit their migration and invasion through G2/M phase arrest, which suggests the complex could act as a potential tumour-targeting inhibitor in future clinical applications.

Currently, effective drugs for triple-negative breast cancer (TNBC) are lacking in clinics. c-myc is one of the core members during TNBC tumorigenesis, and G-rich sequences in the promoter region can form a G-quadruplex conformation, indicating that the c-myc inhibitor is a possible strategy to fight cancer. Herein, a series of chiral ruthenium(II) complexes ([Ru(bpy)₂(DPPZ-R)](ClO₄)₂, Λ/Δ−1: R = -H, Λ/Δ−2: R = -Br, Λ/Δ−3: R = -C≡C(C₆H₄)NH₂) were researched based on their interaction with c-myc G-quadruplex DNA. Λ−3 and Δ−3 show high affinity and stability to decrease their replication. Additional studies showed that Λ−3 and Δ−3 exhibit higher inhibition against different tumor cells than other molecules. Δ−3 decreases the viability of MDA-MB-231 cells with an IC₅₀ of 25.51 μM, which is comparable with that of cisplatin, with an IC₅₀ of 25.9 μM. Moreover, Δ−3 exhibits acceptable cytotoxic activity against MDA-MB-231 cells in a zebrafish xenograft breast cancer model. Further studies suggested that Δ−3 decreases the viability of MDA-MB-231 cells predominantly through DNA-damage-mediated apoptosis, which may be because Δ−3 can induce DNA damage. In summary, the results indicate that Ru(II) complexes containing alkinyl groups can be developed as c-myc G-quadruplex DNA binders to block TNBC progression.