Substituent effects of cyclic naphthalene diimide on G-quadruplex binding and the inhibition of cancer cell growth.

Interaction of cyclic naphthalene diimide derivatives (cNDIs), 1-4, with TA-core and c-myc as G-quartet (G4) DNA was studied under dilute or molecular crowding condition. Binding study for TA-core based on an isothermal titration calorimetry showed that 1-4 has 106 M-1 order of binding affinity with the following order: 1 > 4 > 2 > 3 under both conditions. Meting temperature (Tm) of TA-core obtained from the temperature dependence of circular dichroism spectra shows that TA-core was most stabilized by 4, which is in agreement with the result of PCR stop assay and the stabilization effect for 1-3 was correlated with their binding affinity under dilute condition. 3 showed specific growth inhibition of cancer cell line Ca9-22 at <0.03 µM of IC50, with no inhibitory effect against normal bone marrow cells. 3, which has highest value of ΔH/ΔG, shows the highest inhibition ability for Ca9-22, carrying a highest expression level of telomerase mRNA.

Evaluating GPT-4V's performance in the Japanese national dental examination: A challenge explored.

Background/purpose: Rapid advancements in AI technology have led to significant interest in its application across various fields, including medicine and dentistry. This study aimed to assess the capabilities of ChatGPT-4V with image recognition in answering image-based questions from the Japanese National Dental Examination (JNDE) to explore its potential as an educational support tool for dental students. Materials and methods: The dataset used questions from the JNDE, which was conducted in January 2023, with a focus on image-related queries. ChatGPT-4V was utilized, and standardized prompts, question texts, and images were input. Data and statistical analyses were conducted using Qlik Sense® and GraphPad Prism. Results: The overall correct response rate of ChatGPT-4V for image-based JNDE questions was 35.0 %. The correct response rates were 57.1 % for compulsory questions, 43.6 % for general questions, and 28.6 % for clinical practical questions. In specialties like Dental Anesthesiology and Endodontics, ChatGPT-4V achieved correct response rates above 70 %, while response rates for Orthodontics and Oral Surgery were lower. A higher number of images in questions was correlated with lower accuracy, suggesting an impact of the number of images on correct and incorrect responses. Conclusion: While innovative, ChatGPT-4V's image recognition feature exhibited limitations, especially in handling image-intensive and complex clinical practical questions, and is not yet fully suitable as an educational support tool for dental students at its current stage. Further technological refinement and re-evaluation with a broader dataset are recommended.

Evaluating the efficacy of leading large language models in the Japanese national dental hygienist examination: A comparative analysis of ChatGPT, Bard, and Bing Chat.

Background/purpose: Large language models (LLMs) such as OpenAI's ChatGPT, Google's Bard, and Microsoft's Bing Chat have shown potential as educational tools in the medical and dental fields. This study evaluated their effectiveness using questions from the Japanese national dental hygienist examination, focusing on textual information only. Materials and methods: We analyzed 73 questions from the 32nd Japanese national dental hygienist examination, conducted in March 2023, using LLMs ChatGPT-3.5, GPT-4, Bard, and Bing Chat. Each question was categorized into one of nine domains. Standardized prompts were used for all LLMs, and Fisher's exact test was applied for statistical analysis. Results: GPT-4 achieved the highest accuracy (75.3%), followed by Bing (68.5%), Bard (66.7%), and GPT-3.5 (63.0%). There were no statistically significant differences between the LLMs. The performance varied across different question categories, with all models excelling in the 'Disease mechanism and promotion of recovery process' category (100% accuracy). GPT-4 generally outperformed other models, especially in multi-answer questions. Conclusion: GPT-4 demonstrated the highest overall accuracy among the LLMs tested, indicating its superior potential as an educational support tool in dental hygiene studies. The study highlights the varied performance of different LLMs across various question categories. While GPT-4 is currently the most effective, the capabilities of LLMs in educational settings are subject to continual change and improvement.

Cyclic anthraquinone derivatives, unique G-quadruplex binders, selectively induce cancer cell apoptosis and inhibit tumor growth.

Cyclic anthraquinone derivatives (cAQs), which link two side chains of 1,5-disubstituted anthraquinone as a threading DNA intercalator, have been developed as G-quartet (G4) DNA-specific ligands. Among the cAQs, cAQ-mBen linked through the 1,3-position of benzene had the strongest affinity for G4 recognition and stabilization in vitro and was confirmed to bind to the G4 structure in vivo, selectively inhibiting cancer cell proliferation in correlation with telomerase expression levels and triggering cell apoptosis. RNA-sequencing analysis further indicated that differentially expressed genes regulated by cAQ-mBen were profiled with more potential quadruplex-forming sequences. In the treatment of the tumor-bearing mouse model, cAQ-mBen could effectively reduce tumor tissue and had less adverse effects on healthy tissue. These results suggest that cAQ-mBen can be a potential cancer therapeutic agent as a G4 binder.

Subdomain IIIA of dog albumin contains a binding site similar to site II of human albumin.

Dog albumin contains a specific drug-binding site that binds most of the site II ligands of human albumin. This study was undertaken to elucidate the structural configuration of this binding site using a photoaffinity labeling technique. Dog albumin and albumins of other animal species were photolabeled with [(14)C]ketoprofen. The photolabeled albumins were cleaved with cyanogen bromide (CNBr) and analyzed autoradiographically after electrophoretic separation. A 11.6-kDa CNBr fragment of the photolabeled dog albumin was found to have incorporated most of the radioactivity. Site II ligands of human albumin inhibited photoincorporation of radioactivity to this fragment. The binding constants of human and dog albumins ranged from 10 to 12 x 10(5) M(-1), at least twice as high as those of rat, rabbit, and bovine albumins. Edman degradation was performed to elucidate the amino acid sequence of the photolabeled peptide derived from further digestion of the dog 11.6-kDa CNBr fragment with lysyl endopeptidase. The sequence was XXSESLVXRX, which corresponds to Cys(476)-Arg(485) of dog albumin. Dog albumin contains a binding site that may have a binding microenvironment similar to that of site II on human albumin. Therefore, dog may be a better experimental animal for data extrapolation from animal to human with regard to site II drug-drug interactions.

Kinetic studies of covalent binding between N-acetyl-L-cysteine and human serum albumin through a mixed-disulfide using an N-methylpyridinium polymer-based column.

The binding properties of the disulfide covalent bond between N-acetyl-L-cysteine (NAC) and human serum albumin (HSA) were investigated. HSA, purified from either healthy subjects or renal failure patients, was incubated with NAC in buffer and analyzed by 4VP-EG-Me column chromatography, which can distinguish between the redox states of the only free thiol of HSA. Although intact HSA was found to consist of mainly three sub-types, marcaptoalbumin (HMA), cysteine-bound nonmercaptoalbumin (HNA(Cys)) and a further oxidized form (HNA(oxy)), the formation of a new type of nonmercaptoalbumin (HNA(NAC)) was confirmed after incubation with NAC. Interestingly, NAC rapidly dissociated Cys from HNA(Cys) and NAC itself bound very slowly to HSA. These findings suggest that the interaction between NAC and HSA proceeds in a 2-step processes. The first-order binding and dissociation rate constants of NAC to healthy HSA (k(on,NAC)) and Cys from healthy HNA(Cys) (k(off,Cys)) were approximately 0.0032 and 1.3 (h(-1)), respectively. On the other hand, HSA from renal failure patients showed decreased HMA and increased HNA(Cys). The k(on,NAC) and k(off,Cys) were 0.0094 and 0.45 (h(-1)), respectively, suggesting that the pathological state may affect the binding properties of HSA and NAC.