Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive neoplastic diseases of the pancreas with fatal proliferation and metastasis and no medicine available for treatment. From an Antarctica sponge-derived fungus, Aspergillus insulicola HDN151418, four new nitrobenzoyl sesquiterpenoids, namely, insulicolides D-G (1-4), were isolated. Compounds 3 and 4 exhibited selective inhibition against human PDAC cell lines. Further studies indicated that compound 4 could significantly suppress cell proliferation to induce apoptosis and blocked migration and invasion of PDAC cells. Compound 4 could also avoid resistance and improved the therapeutic effect of the chemotherapy drug gemcitabine. A preliminary mechanism study showed that compound 4 can significantly inhibit the expression of EGFR and XIAP in PDAC cells. Altogether, 4 is a potential lead compound for anti-PDAC drug research.