Conventional therapy regimens for pancreatic cancer (PC) are surgical resection and systemic gemcitabine based chemotherapy. Recent studies showed that curcumin could potentiate the anticancer effect of gemcitabine in PC. However, due to its poor water solubility, effective bioavailability of curcumin is insufficient, resulting in poor efficacy. To address this issue, mesoporous silica nanoparticles (MSN) were prepared by the sol–gel method, then loaded with curcumin (Cur), coated with polyethylene glycol (PEG), and finally conjugated with the targeting moiety transferrin (Tf) to target human PC cells. TEM analysis revealed that uniform sized spherical MSN formed with an average size of 100 nm, which increased to 120 nm after PEG coating on MSN surface. Confocal microscopy proved that curcumin uptake being seven-times higher for MSN–NH2–Cur–PEG–Tf, when compared to free curcumin. The in vitro cytotoxicity study on MIA PaCa-2 cells showed that MSN–NH2–Cur–PEG–Tf exhibited three-fold higher cytotoxicity than free curcumin. On the basis of the encouraging in vitro cytotoxicity results obtained, preclinical assessment of antitumor efficacy in MIA PaCa-2 subcutaneous xenograft model proves that both MSN–NH2–Cur–PEG and MSN–NH2–Cur–PEG–Tf inhibit tumor growth and minimize distant metastasis to major organ sites. The in vitro studies also proved that nanoparticles can enhance the sensitization effect, caused by curcumin on cancer cells, which help the gemcitabine to kill a higher percentage of cancer cells. Hence, we propose that transferrin targeted, PEGylated, mesoporous silica nanoparticles can be used as a carrier to deliver curcumin, and used in addition to gemcitabine to reduce disease burden significantly for pancreatic cancer patients.

Substantial number of breast cancer (BC) patients undergoing radiation therapy (RT) develop local recurrence over time. During RT therapy, cells can gradually acquire resistance implying adaptive radioresistance. Here we probe the mechanisms underlying this acquired resistance by first establishing radioresistant lines using ZR-75-1 and MCF-7 BC cells through repeated exposure to sub-lethal fractionated dose of 2Gy up to 15 fractions. Radioresistance was found to be associated with increased cancer stem cells (CSCs), and elevated EpCAM expression in the cell population. A retrospective analysis of TCGA dataset indicated positive correlation of high EpCAM expression with poor response to RT. Intriguingly, elevated EpCAM expression in the radioresistant CSCs raise the bigger question of how this biomarker expression contributes during radiation treatment in BC. Thereafter, we establish EpCAM overexpressing ZR-75-1 cells (ZR-75-1EpCAM), which conferred radioresistance, increased stemness through enhanced AKT activation and induced a hybrid epithelial/mesenchymal phenotype with enhanced contractility and invasiveness. In line with these observations, orthotopic implantation of ZR-75-1EpCAM cells exhibited faster growth, lesser sensitivity to radiation therapy and increased lung metastasis than baseline ZR-75-1 cells in mice. In summary, this study shows that similar to radioresistant BC cells, EpCAM overexpressing cells show high degree of plasticity and heterogeneity which ultimately induces radioresistant and metastatic behavior of cancer cells, thus aggravating the disease condition.