We developed supramolecular self-assembled nanoparticles for targeting the endoplasmic reticulum (ER) in cancer cells.

The endoplasmic reticulum (ER) primarily guides protein synthesis, folding, transport, and lipid biosynthesis inside the cells. As a result, dysregulation in those cellular functions leading to ER stress has recently emerged as one of the hallmarks of cancer. Yet, precise navigation in the ER in cancer cells has continued to be a formidable task. Herein, we engineered a lipid nanoparticle (17AAG-ER-NP) containing (a) ER targeting moiety (Tosyl), (b) fluorescent tag with DNA damaging capability (1,8-naphthalimide), and (c) ER stress inducer (17AAG, Hsp90 inhibitor). These lipidic nanoparticles were confined in the ER of HeLa cells over 6 h through caveolin-controlled endocytosis confirmed by confocal microscopy. Western blot analysis, fluorescent microscopy, and flow cytometry studies confirmed that 17AAG-ER-NPs can concurrently activate ER stress and nuclear DNA impairment for arresting the cell cycle in the G2-M phase to elicit late apoptosis, followed by cell death, in a greatly augmented manner compared to free drugs. Interestingly, this nanoparticle-mediated ER stress activated autophagy, which was suppressed through a cocktail treatment with 17AAG-ER-NPs and chloroquine (autophagy inhibitor), prompted remarkable HeLa cell killing at submicromolar concentration. This nanoplatform can support new tools to impair multiple targets in the ER for future cancer therapy.

Mitochondrion, the powerhouse of the cells, controls bioenergetics, biosynthesis, metabolism, and signaling. Consequently, it has become an unorthodox target for cancer therapeutics. However, specific targeting of mitochondria into subcellular milieu in cancer cells remains a major challenge. To address this, we have engineered polyethylenimine cloaked positively charged self-assembled graphene oxide nanoparticle (PEI-GTC-NP) comprising topotecan and cisplatin concurrently. These PEI-GTC-NPs effectively homed into mitochondria in HeLa cervical cancer cells at 6 h and impaired mitochondria leading to reactive oxygen species generation followed by remarkably improved cancer cell death. This platform can be used for specific subcellular organelle targeting for future cancer therapy.

This report describes the hitherto unobserved cisplatin induced self-assembly of 2D-graphene oxide sheets into 3D-spherical nano-scale particles. These nanoparticles can encompass dual DNA damaging drugs simultaneously. A combination of confocal microscopy, gel electrophoresis and flow cytometry studies clearly demonstrated that these novel nanoparticles can internalize into cancer cells by endocytosis, localize into lysosomes, and damage DNA, leading to apoptosis. Cell viability assays indicated that these nanoparticles were more cytotoxic towards cancer cells compared to healthy cells.

Endoplasmic reticulum is one of the vital organelles primarily involved in protein synthesis, folding, transport and lipid biosynthesis. However, in cancer cells its functions are dysregulated leading to ER stress....