Demethoxymurrapanine, an indole-naphthoquinone alkaloid, inhibits the proliferation of oral cancer cells without major side effects on normal cells

The interaction of isoquinoline alkaloid crebanine with immunoglobulin G and cytotoxic effects toward MCF-7 breast cancer cell line

In this study, the interaction of crebanine, an isoquinoline alkaloid, with immunoglobulin G (IgG) was evaluated. Subsequently, the anticancer effects of crebanine in MCF-7 breast cancer cells were assessed. The results demonstrate that static quenching plays a key role in the fluorescence quenching of the IgG by crebanine, and some embedded hydrophobic patches of the IgG are exposed upon interaction with crebanine, while the characteristic β-sheet conformation of the IgG was almost preserved. Theoretical studies also show that several hydrophilic and hydrophobic residues play a crucial role in the formation of hydrogen bonds between crebanine and IgG, along with the stability of the complex. Cellular studies indicate that crebanine induces selective anticancer effects in MCF-7 cells (IC50: 36.76 μM) compared to human embryonic kidney cells (HEK-293, IC50: 723.77 μM) through the inhibition of colony formation, induction of oxidative stress and lipid peroxidation, upregulation of the Bax/Bcl-2 ratio, and cytochrome c release, which are indicative of the intrinsic apoptosis pathway. In conclusion, this study provides valuable information regarding the protein binding affinity and anticancer activity of crebanine, which are essential factors for determining the pharmacological activity of small molecules as drug candidates.

6-n-Butoxy-10-nitro-12,13-dioxa-11-azatricyclo[7.3.1.02,7]trideca-2,4,6,10-tetraene Improves the X-ray Sensitivity on Inhibiting Proliferation and Promoting Oxidative Stress and Apoptosis of Oral Cancer Cells

This in vitro study examines the anti-oral cancer effects and mechanisms of a combined X-ray/SK2 treatment, i.e., X-ray and 6-n-butoxy-10-nitro-12,13-dioxa-11-azatricyclo[7.3.1.02,7]trideca-2,4,6,10-tetraene (SK2). ATP cell viability and flow cytometry-based cell cycle, apoptosis, oxidative stress, and DNA damage assessments were conducted. The X-ray/SK2 treatment exhibited lower viability in oral cancer (Ca9-22 and CAL 27) cells than in normal (Smulow-Glickman, S-G) cells, i.e., 32.0%, 46.1% vs. 59.0%, which showed more antiproliferative changes than with X-ray or SK2 treatment. Oral cancer cells under X-ray/SK2 treatment showed slight subG1 and G2/M increments and induced high annexin V-monitored apoptosis compared to X-ray or SK2 treatment. The X-ray/SK2 treatment showed higher caspase 3 and 8 levels for oral cancer cells than other treatments. X-ray/SK2 showed a higher caspase 9 level in CAL 27 cells than other treatments, while Ca9-22 cells showed similar levels under X-ray and/or SK2. The X-ray/SK2 treatment showed higher reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) depletion than other treatments. Meanwhile, the mitochondrial superoxide (MitoSOX) and glutathione levels in X-ray/SK2 treatment did not exhibit the highest rank compared to others. Moreover, oral cancer cells had higher γH2AX and/or 8-hydroxy-2-deoxyguanosine levels from X-ray/SK2 treatment than others. All these measurements for X-ray/SK2 in oral cancer cells were higher than in normal cells and attenuated by N-acetylcysteine. In conclusion, X-ray/SK2 treatment showed ROS-dependent enhanced antiproliferative, apoptotic, and DNA damage effects in oral cancer cells with a lower cytotoxic influence on normal cells.