Jian Gao

Multiple myeloma (MM) still lacks curative therapies, creating an urgent demand for innovative agents targeting unique molecular vulnerabilities. G-quadruplex (G4) stabilization modulates oncogenic regulatory regions and displays potent preclinical antitumor effects. Nevertheless, most existing G4 ligands act on single G4 motifs. Pan-G4 agents capable of perturbing multiple oncogenic pathways are scarce, while conventional high-throughput screening is costly and labor-intensive. Herein, we constructed a repurposing-driven screening pipeline combining curated fluorescence resonance energy transfer (FRET)-derived melting-temperature shift (ΔTm) data sets, 1024-bit Chemistry Development Kit (CDK) molecular fingerprints, three machine-learning classifiers, and multi-G4 molecular docking. In nested cross-validation, our Random Forest (RF) classifier yielded a receiver operating characteristic area under the curve (ROC AUC) of 0.840 and a Matthews correlation coefficient (MCC) of 0.708, superior to label-randomized controls. Consensus screening of 4270 compounds from the TargetMol Anticancer Library yielded 812 high-confidence hits; the top-ranked 487 candidates underwent docking against four structurally diverse oncogenic G4s (c-Myc, c-KIT, Bcl-2, k-RAS). CCT245737 ranked in the top ten across all four independent docking analyses. Functional assays revealed that CCT245737 suppressed the viability of U266 and RPMI-8226 MM cells (IC50 = 0.58 ± 0.06 and 0.68 ± 0.04 μM) and enhanced nuclear BG4 signals. FRET-melting and NMM-displacement assays verified its concentration-dependent stabilization of the four G4s with minimal duplex-DNA interference. qPCR and immunoblotting confirmed downregulation of c-Myc, c-KIT, Bcl-2, and k-RAS at both mRNA and protein levels. In summary, CCT245737 is validated as a promising pan-G4 ligand, and our FRET-guided workflow offers a feasible repurposing strategy for discovering anti-MM G4-targeted therapeutics.

Multiple myeloma (MM) is a malignant blood cancer marked by severe bone destruction and immune microenvironment disruption. Yet relapse and drug resistance remain major clinical challenges. Tanshinone IIA (TIIA) exhibits potent antitumor activity, but its molecular targets and mechanisms in MM remain unclear. Here, we systematically elucidate TIIA’s pharmacological mechanisms in MM using network pharmacology, transcriptomics, molecular docking, molecular dynamics (MD) simulations, and in vitro cellular experiments. Histone deacetylase 6 (HDAC6) was identified as a key prognostic target in MM via integrative bioinformatics─combining cross-database analysis, machine learning (LASSO, SVM-RFE, random forest), and survival validation in the MMRF-CoMMpass cohort. Molecular docking and MD simulations showed stable binding of TIIA to HDAC6. In vitro, TIIA directly inhibited HDAC6 enzymatic activity and selectively killed U266 and RPMI 8226 myeloma cells in a dose-dependent manner, with minimal toxicity to normal cells. Additionally, gene set enrichment analysis (GSEA) and single-sample GSEA (ssGSEA) immune profiling using the LM22 signature suggested that HDAC6 participates in microenvironmental remodeling by modulating cell adhesion-mediated resistance and orchestrating an immunosuppressive niche characterized by monocyte depletion. This study highlights for the first time the critical role of HDAC6 in TIIA-mediated antimyeloma activity and provides novel mechanistic insights and potential targeted therapeutic strategies for the treatment of MM.

The c-Myc oncogene is crucial in tumorigenesis. Although it is a promising therapeutic target, its protein lacks a conventional drug-binding pocket, making it traditionally “undruggable”. Recent studies show that the c-Myc promoter can form a G-quadruplex (G4) structure, which suppresses transcription and offers a new strategy for indirect inhibition. In this study, structure-based virtual screening was performed using the c-Myc G4 crystal structure to screen the ChemDiv compound library, aiming to identify small molecules that bind to the G4 structure. Candidate compounds were evaluated in preliminary in vitro assays for biological activity. The results showed that Y502-3888 binds to the c-Myc G4 and downregulates c-Myc expression at both mRNA and protein levels. Collectively, these findings support the potential of Y502-3888 as a c-Myc G4 binder for the treatment of multiple myeloma (MM), providing a foundation for future development of anticancer agents targeting the c-Myc G4. Graphical abstract

RNA modifications regulate phenotype and function of macrophages by regulating RNA translation, splicing, and stability. However, the role of N ⁷ -methylguanosine (m ⁷ G) modification in macrophages and inflammation remains unexplored. In this study, we observed elevated levels of the methyltransferase METTL1 and m ⁷ G modifications in macrophages from mouse and human tissues during acute kidney injury (AKI). METTL1 deficiency in myeloid cells mitigated multiorgan inflammation induced by cecal ligation and puncture and renal ischemia/reperfusion. Genetic deletion of METTL1 inhibited macrophage proinflammatory responses. We identified internal Sarm1 messenger RNA (mRNA) as a target of m ⁷ G modification that controls macrophage metabolic reprogramming. METTL1 deficiency in macrophages inhibited metabolic reprogramming, which was reversed by SARM1 overexpression that induced NAD ⁺ decline. Pharmacologically, SA91-0178, a specific METTL1 inhibitor, effectively alleviated tissue injury during septic inflammation. Collectively, our findings suggest that m ⁷ G modification enhances the stability of Sarm1 mRNA, thereby resulting in NAD ⁺ imbalance in macrophages, indicating that METTL1 may serve as a potential therapeutic target for systemic inflammation.

Background: This study aims to investigate the impact of coal dust (silicon dioxide) exposure on dyslipidemia and its underlying mechanisms, with a focus on the association between coal dust exposure and hepatic metabolic disorders. Methods: Clinical data were collected from 5433 coal mine workers to compare the incidence of dyslipidemia between the dust-exposed group and the non-exposed group. A mouse model of silicon dioxide exposure was established to observe hepatic fat accumulation and pathological changes. Liver tissue sequencing was performed to screen for key differential genes. In vitro cell experiments were utilized to identify the molecular mechanisms underlying hepatocyte metabolic abnormalities induced by silicon dioxide exposure. Results: Clinical data revealed that 69.2% of miners in the dust-exposed group developed dyslipidemia, which was higher than the 30.7% in the non-exposed group. Animal data showed that silicon dioxide exposure led to hepatic fat deposition and pathological damage, with the degree of injury positively correlated with exposure time. Liver sequencing identified a significant upregulation of the FMO3 (flavin monooxygenase 3) gene in mouse liver tissue following silicon dioxide exposure, accompanied by enhanced inflammatory responses. Mechanistic studies demonstrated that silicon dioxide activates Kupffer cells to secrete IL-6 (interleukin-6), which induces high expression of FMO3 in hepatocytes through the PKC/YY1 signaling pathway, thereby disrupting lipid metabolism. Conclusions: Silicon dioxide exposure can promote the upregulation of FMO3 expression in hepatocytes by activating Kupffer cells to release IL-6 via the PKC/YY1 pathway, ultimately leading to lipid metabolic disorders and dyslipidemia

Neuropathic pain is a type of pain caused by an injury or disease of the somatosensory nervous system. Currently, there is still absence of effective therapeutic drugs for neuropathic pain, so developing new therapeutic drugs is urgently needed. In the present study, we observed the effect of Comp 6d, a novel silent information regulator 1 (SIRT1) activator synthesized in our laboratory, on neuropathic pain and investigated the mechanisms involved. We found that both intrathecal and intraperitoneal injections of Comp 6d effectively alleviated neuropathic pain induced by chronic constriction injury (CCI) or spared nerve injury (SNI). However, the effect of Comp 6d on neuropathic pain was abolished in SIRT1 knockout mice. These results demonstrated that Comp 6d alleviated neuropathic pain by specifically activating SIRT1 in the spinal cord. Moreover, long-term intraperitoneal injection of Comp 6d had no significant side effects on heart, liver and kidney in SNI mice. Further study showed that the improvement of neuropathic pain by Comp 6d was mediated by the downregulation of mGluR1/5 levels and the subsequent inhibition of spinal neuronal activation. Taken together, the present findings suggest that the novel SIRT1 activator Comp 6d inhibits the activation of spinal cord neurons via the SIRT1-mGluR1/5 pathway, thereby attenuating neuropathic pain. Comp 6d is expected to be an effective therapeutic agent for neuropathic pain.

Overexpression of c‐Myc is a key factor in the development of leukemia and other malignancies, highlighting the urgent need for novel drugs to inhibit c‐Myc protein levels. DNA G‐quadruplexes (G4) have emerged as potential regulatory targets for c‐Myc expression. Previous studies identified trovafloxacin, a topoisomerase II inhibitor, as a novel c‐Myc G4 stabilizer. In this study, virtual screening based on structural similarity led to the identification of nine derivatives of trovafloxacin, among which voreloxin exhibited potent cytotoxicity in multiple myeloma cells and showed promising therapeutic efficacy in leukemia cells. FRET assays demonstrated that voreloxin specifically stabilized the G4 structures of c‐Myc and Bcl‐2, with minimal effects on the G4 structures of other oncogenes. Moreover, voreloxin significantly reduced the expression levels of c‐Myc and Bcl‐2 in THP‐1 and MOLM‐13 cells. Molecular docking, molecular dynamics (MD) simulations, and MM/GBSA calculations further confirmed the stable binding of voreloxin to both c‐Myc and Bcl‐2 G4s, primarily driven by π‐π stacking and hydrogen bonding interactions. These findings provide valuable insights for the development of G4‐targeting drugs for cancer therapy.