Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, highlighting the need to identify novel bioactive compounds with antitumor potential. Natural products constitute a valuable source of molecules with anticancer activity. In this study, we performed a comparative analysis of two classes of natural compounds—sesquiterpene lactones (achillin and polymatin A) and naphthoquinones (α, β-lapachone and lapachol)—in human PDAC cell lines on cell proliferation, metabolic activity and cell death induction and early mitochondrial alterations. Achillin showed limited antiproliferative, metabolic, and cytotoxic activity, whereas polymatin A exhibited activity in the micromolar range, yielding LC₅₀ values of 16.11 ± 2.27 μM and 20.00 ± 1.90 μM for PANC-1 and MIAPaCa-2 cells, respectively. The naphtoquinones α- and β-lapachone effectively inhibited proliferation and metabolic activity and triggered cell death in both PDAC cell lines, with β-lapachone consistently displaying the highest activity with an LC₅₀ of 4.00 ± 0.07 μM for PANC-1 cells and 3.89 ± 0.50 μM for MIAPaCa-2. Interestingly, achillin, polymatin A, α- and β-lapachone selectively induced cell death while sparing PBMCs. In contrast, lapachol showed weak activity, failing to achieve 50% inhibition or cell death within the tested concentration range and lacking tumor selectivity. Mechanistically, quinone derivatives promoted early mitochondrial superoxide modulation and membrane depolarization, consistent with a redox-active profile, whereas sesquiterpene lactones induced mitochondrial depolarization with limited mitochondrial superoxide overproduction, suggesting a distinct bioenergetic disruption phenotype. Overall, these findings highlight structure–activity relationships among natural compounds and support further investigation of achillin, polymatin A and α,β-lapachone as promising molecular scaffolds in PDAC research.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy characterized by poor prognosis and limited response to gemcitabine, the standard first-line chemotherapy. One major contributor to chemoresistance is autophagy, a process frequently upregulated in PDAC. In this study, we examined the ability of type I interferons (IFNα2b and IFNβ1a) to modulate autophagy and disturb tumor cell resistance to gemcitabine. PDAC cells were treated with increasing concentrations of IFNα2b or IFNβ1a, and cell proliferation was assessed by [³H]-thymidine incorporation. Apoptosis was evaluated by TUNEL staining following treatments with interferons and/or gemcitabine. Autophagy was analyzed by Western blot for LC3B and by quantifying autophagic flux using mCher-ry-EGFP-LC3B-transfected cells in the presence or absence of lysosomal inhibitors. We found that IFNα2b promoted autophagic flux and decreased gemcitabine-induced apop-tosis, indicating a cytoprotective role. In contrast, IFNβ1a inhibited autophagosome for-mation and significantly enhanced apoptosis in gemcitabine-treated cells. Our findings highlight the contrasting roles of IFNα2b and IFNβ1a in autophagy regulation and sug-gest that IFNβ1a, by inhibiting protective autophagy, may sensitize PDAC cells to chemo-therapy. This positions IFNβ1a as a promising adjuvant to overcome chemoresistance in PDAC treatment.