An Intrinsic Mitochondrial Pathway Is Required for Phytic Acid-Chitosan-Iron Oxide Nanocomposite (Phy-CS-MNP) to Induce G₀/G₁ Cell Cycle Arrest and Apoptosis in the Human Colorectal Cancer (HT-29) Cell Line.

Magnetic iron oxide nanoparticles are among the most useful metal nanoparticles in biomedical applications. A previous study had confirmed that phytic acid-chitosan-iron oxide nanocomposite (Phy-CS-MNP) exhibited antiproliferative activity towards human colorectal cancer (HT-29) cells. Hence, in this work, we explored the in vitro cytotoxicity activity and mechanistic action of Phy-CS-MNP nanocomposite in modulating gene and protein expression profiles in HT-29 cell lines. Cell cycle arrest and apoptosis were evaluated by NovoCyte Flow Cytometer. The mRNA changes (cyclin-dependent kinase 4 (), vascular endothelial growth factor A (), c-Jun N-terminal kinase 1 (), inducible nitric oxide synthase (), and matrix metallopeptidase 9 ()) and protein expression (nuclear factor-kappa B () and cytochrome c) were assessed by quantitative real-time polymerase chain reaction (PCR) and western blotting, respectively. The data from our study demonstrated that treatment with Phy-CS-MNP nanocomposite triggered apoptosis and G₀/G₁ cell cycle arrest. The transcriptional activity of and was upregulated after treatment with 90 μg/mL Phy-CS-MNP nanocomposite. Our results suggested that Phy-CS-MNP nanocomposite induced apoptosis and cell cycle arrest via an intrinsic mitochondrial pathway through modulation of Bax and Bcl-2 and the release of cytochrome c from the mitochondria into the cytosol.