Background: Glioblastoma (GBM) is the most aggressive malignancy of the central nervous system (CNS) and is characterized by poor prognosis and significant resistance to available treatments. Surgery, radiation therapy, and chemotherapy are the standard treatments; however, their efficacy is often limited by resistance. Resveratrol (RES), a naturally occurring polyphenol with antioxidant properties, has shown significant anticancer effects through inhibition of multiple cellular pathways. However, our earlier research revealed that the LN428 cell exhibited resistance, while the U251 cell showed sensitivity to RES monotherapy. Hence, RES and AG490, a JAK2 inhibitor, were used to overcome GBM cell resistance, which might enhance therapeutic efficacy. Methods: Human GBM cell lines LN428 and U251 were used. CCK-8, H&E staining, transwell, wound healing, calcein AM/PI, and flow cytometry assays were performed to evaluate cell proliferation, migration, and apoptosis. Molecular docking was performed to analyze the binding energy. Western blot, immunocytochemistry (ICC), and immunofluorescence (IF) were used to assess protein expression following treatment with RES, AG490, and their combination. Results: The results revealed that U251 cells were more sensitive to RES, AG490, and RES + AG490 than LN428 cells. Additionally, the combination of both compounds significantly reduced cell viability, proliferation, and migration, while increasing apoptosis in the LN428 and U251 cell lines. Moreover, the combination of RES and AG490 led to increased BAX protein expression while decreasing BCL-2 expression in LN428 and U251 cell lines. Notably, the monotherapy administration of RES did not significantly inhibit STAT3 or pSTAT3 protein expression in LN428 cells, while combination therapy significantly inhibited the expression of these proteins in LN428 and U251 cell lines. Conclusions: The concurrent administration of RES and AG490 effectively inhibited the JAK2/STAT3 signalling pathway and enhanced antitumor effects in GBM cells, indicating their potential as a therapeutic strategy.

An increasing body of evidence suggests that lactate and its associated post-translational modification, lactylation, are critically involved in the aggressive progression of melanoma and represent promising therapeutic targets. Rhein, a bioactive compound derived from rhubarb-a traditional Chinese medicinal herb-has shown anti-cancer properties in multiple tumor types. Nevertheless, its role in melanoma remains poorly understood. This study investigated the role of Rhein in melanoma and uncovered the underlying mechanism. Cell growth and cell death were investigated by colony formation and Propidium Iodide (PI) Staining. The RNA sequencing analysis was used to identify the altered genes and miRNAs. Targeted Metabolomics Analysis was used to investigate the altered metabolites. In this study, we demonstrate that Rhein effectively suppresses melanoma cell proliferation and migration while inducing apoptosis in vitro, and also inhibits tumor growth in vivo. Moreover, Rhein strengthens the host's anti-tumor immune response and counteracts tumor immune evasion. Mechanistically, Rhein significantly reduces LDHA expression, leading to decrease intracellular and extracellular lactic acid levels. Restoring LDHA expression or supplementing lactate diminishes Rhein's anti-melanoma activity and facilitates immune escape. We further show that Rhein downregulates PLK1 by reducing histone H3K18 lactylation at the PLK1 promoter. Notably, our results reveal that Rhein treatment markedly increases miR-27a-5p expression. Upregulated miR-27a-5p suppresses LDHA, subsequently lowering both lactic acid accumulation and PLK1 levels. Taken together, these data highlight the critical involvement of the miR-27a-5p/LDHA/lactate/PLK1 signaling axis in mediating Rhein's anti-melanoma effects, suggesting its potential as a therapeutic strategy for melanoma.

Background: Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor with limited treatment options. Tumors harboring the BRAF^V600E mutation exhibit aggressive behavior and present therapeutic challenges. Although dabrafenib/trametinib (D+T) target the BRAF/MAPK pathway and show efficacy in BRAF^V600E mutant melanoma, their effectiveness against GBM remains unclear. RES demonstrates anti-GBM activity through the inhibition of multiple signaling pathways. This study evaluated the therapeutic potential of RES either in monotherapy or in combination with D+T in GBM cells with and without the BRAF^V600E mutation. Methods: BRAF^V600E mutational status was confirmed in LN428 and U251 GBM cell lines using Sanger sequencing. Cell proliferation and viability was assessed by CCK-8, EdU assay and Calcein AM/PI staining, cell morphology by H&E staining, cell migration by Transwell assay, and apoptosis by TUNEL assay. The protein expressions of BRAF, pERK, and pSTAT3 were analyzed by Western blot, immunocytochemistry (ICC), and immunofluorescence (IF) following treatment with RES, D+T, or their combination. Statistical significance was determined using one-way ANOVA followed by Dunnett’s post hoc test with p < 0.05. Results: Sanger sequencing confirmed the presence of the BRAF^V600E mutation in the LN428 cells and its absence in the U251 cells. In the BRAF^V600E mutant LN428 cells, neither RES, D+T, nor their combination inhibited cell proliferation or migration, nor did they induce apoptosis. In contrast, RES monotherapy significantly suppressed proliferation, reduced migration, and induced apoptosis in the wild-type U251 cells, while D+T showed minimal inhibitory effects in both cell lines. Western blotting, ICC, and IF analyses revealed that RES significantly downregulated both pERK and pSTAT3 expression in the U251 cells but failed to produce similar effects in the LN428 cells. Notably, D+T treatment induced marked upregulation of pSTAT3 in both cell lines, which was effectively reversed by RES treatment in the U251 cells but not in the LN428 cells. Conclusions: RES selectively suppressed the MAPK and STAT3 signaling pathway in the BRAF wild-type U251 cells, while demonstrating no significant inhibitory effects in the BRAF mutant LN428 cells. This differential response indicates that mutational background governs MAPK/STAT3 pathway regulation, positioning RES as a promising dual-pathway inhibitor in mutation-stratified GBM therapeutics.