Background: Lung cancer remains the leading cause of cancer-related mortality worldwide, with non-small cell lung cancer (NSCLC) accounting for approximately 85% of all cases. Isorhamnetin (ISO), a natural dietary flavonoid, has demonstrated potent anti-lung cancer activity in cell models. However, its precise mechanism of action within the complex landscape of NSCLC remains to be fully elucidated. Methods: The effects of ISO on NSCLC cell viability, apoptosis, and cell cycle distribution were assessed in A549 and H1650 cells using the MTT assay, Annexin V-FITC/PI staining, and flow cytometry. Wound healing and Transwell assays were employed to evaluate the isorhamnetin impact on cell migration, invasion, and adhesion. To investigate the underlying molecular mechanisms, RNA sequencing (RNA-seq) was performed, followed by validation of key target genes and proteins using qRT-PCR and Western blot analysis. Results: ISO treatment elicited a significant, dose- and time-dependent inhibition of NSCLC cell viability, which coincided with a marked induction of apoptosis. Cell cycle analysis revealed that ISO triggered an S-phase arrest. Transcriptomic profiling identified ELFN1 and TMEM186 as significantly upregulated genes, while SETDB1 was downregulated in a concentration-dependent manner; this was accompanied by a concomitant upregulation of FGFBP1 protein expression. Functionally, ISO effectively suppressed the migratory, invasive, and adhesive capabilities of both cell lines. Conclusions: Our findings demonstrate that ISO exerts a potent anti-proliferative and anti-metastatic effect on NSCLC cells. The underlying mechanism is multifaceted, involving the induction of apoptosis and cell cycle arrest, coupled with the modulation of a novel regulatory network centered on ELFN1, TMEM186, SETDB1, and FGFBP1. These results provide new mechanistic insights into the anti-tumor pharmacology of isorhamnetin and highlight its potential as a therapeutic agent targeting both cancer cells and their supporting microenvironments.

Background: Prostate cancer (PCa) is the leading male urinary malignancy globally. Our previous article demonstrated the anti-PCa activity of Euphorbia humifusa Willd water extract (EHW) and some of its compounds via downregulating AR expression, but the anti-PCa active compounds from Euphorbia humifusa Willd (EH) and their mechanisms of action are yet to be clarified. Thus, the current article studied the in vitro anti-PCa effects of 3,3′-di-O-methylellagic acid (3,3′-di-O-Me-EA) derived from EHW and the related mechanism involved. Methods: 3,3’-di-O-Me-EA was isolated from EHW applying bioassay-guided fractionation. The spectroscopic methods were used to determining the structure of 3,3′-di-O-Me-EA. The drug-likeness and ADMET properties (absorption, distribution, metabolism, excretion, and toxicity) of 3,3′-di-O-Me-EA were analyzed in silico. Molecular docking and real-time surface plasmon resonance (SPR) analysis were performed to measure the interaction of 3,3′-di-O-Me-EA and VDAC1 protein. The viability and apoptosis of 22RV-1 and DU145 PCa cells were determined using MTT and Annexin V-FITC staining assay, respectively. q-PCR and Western blot experiments were used to analyzing the gene and protein expressions of VDAC1. Results: 3,3′-di-O-Me-EA was isolated and purified from EHW with a purity of ≥90.06%, and its structure was identified by HRTOF mass, NMR, and an authentic standard. In silico ADMET analysis indicated its favorable drug-like and pharmacokinetic properties. Molecular docking and SPR results confirmed that 3,3′-di-O-Me-EA could bind with the VDAC1 protein. Moreover, 3,3′-di-O-Me-EA dose- and time-dependently inhibited 22RV-1 and DU145 PCa cell viability, and induced apoptosis in a dose-dependent manner (p < 0.05). RT-qPCR and Western blot results showed that 3,3′-di-O-Me-EA dose-dependently up-regulated VDAC1 gene and protein expression levels in 22RV-1 and DU145 cells (p < 0.05). Meanwhile, in VDAC1-depleted 22RV-1 and DU145 cells, 3,3′-di-O-Me-EA down-regulated VDAC1 gene and protein expression levels, increased cell viability, and inhibited apoptosis compared to 22RV-1 and DU145 cells (p < 0.05). Furthermore, 3,3′-di-O-Me-EA enhanced VDAC1 gene and protein expression levels, inhibited cell viability, and induced apoptosis in VDAC1-overexpressed 22RV-1 and DU145 cells compared with 22RV-1 and DU145 cells (p < 0.05). Overall, EH active compound 3,3′-di-O-Me-EA may inhibit viability and induce apoptosis of 22RV-1 and DU145 PCa cells via up-regulating VDAC1 gene and protein expression levels. Conclusion: The results indicated that the 22RV1 and DU145 PCa cell viability inhibitory effects of 3,3′-di-O-Me-EA isolated from EH may be mediated by induction of apoptosis through up-regulation of VDAC1 gene and protein expression levels.