Insight into OroxylinA-7-O-β-d-Glucuronide-Enriched Oroxylum indicum Bark Extract in Oral Cancer HSC-3 Cell Apoptotic Mechanism: Role of Mitochondrial Microenvironment

Abstract

Oroxylum indicum, of the Bignoniaceae family, has various ethnomedical uses such as an astringent, anti-inflammatory, anti-bronchitis, anti-helminthic and anti-microbial, including anticancer properties. The druggability of OI stem bark extract was determined by its molecular docking interactions with PARP and Caspase-3, two proteins involved in cell survival and death. Note that 50 µg/mL of Oroxylum indicum extract (OIE) showed a significant (p < 0.05%) toxicity to HSC-3 cells. MTT aided cell viability and proliferation assay demonstrated that 50 µg/mL of OIE displayed significant (p < 0.5%) reduction in cell number at 4 h of incubation time. Cell elongation and spindle formation was noticed when HSC-3 cells were treated with 50 µg/mL of OIE. OIE initiated DNA breakage and apoptosis in HSC-3 cells, as evident from DNA ladder assay and calcein/EB staining. Apoptosis potential of OIE is confirmed by flow cytometer and triple-staining (live cell/apoptosis/necrosis) assay. Caspase-3/7 fluorescence quenching (LANCE) assay demonstrated that 50 µg/mL of OIE significantly enhanced the RFU of caspases-3/7, indicating that the apoptosis potential of OIE is probably through the activation of caspases. Immuno-cytochemistry of HSC-3 cells treated with 50 µg/mL of OIE showed a significant reduction in mitochondrial bodies as well as a reduction in RFU in 60 min of incubation time. Immunoblotting studies clearly showed that treatment of HSC-3 cells with OI extract caused caspase-3 activation and PARP deactivation, resulting in apoptotic cell death. Overall, our data indicate that OIE is an effective apoptotic agent for human squamous carcinoma cells and it could be a future cancer chemotherapeutic target.

Chemosensitization of U-87 MG Glioblastoma Cells by Neobavaisoflavone towards Doxorubicin and Etoposide

“…However, it had a limited effect on apoptosis induction ( Figure 2 B). This is consistent with the fact that normal cells are less prone to mitochondrial damage than tumor cells [ 44 ]. On the other hand, the observed effect of NBIF on mitochondria in U-87 MG cells might have contributed to the results that we received previously from the WST-1 test, which is based on the activity of mitochondrial dehydrogenases [ 34 ].…”

“…Alternatively, the decrease in the subpopulation with low mitochondrial membrane potential in U-87 MG cells treated with NBIF could mean that this isoflavone prevents mitochondrial membrane disruption in this cell line, beside the apoptosis intensification. It may be connected, i.a., with mitochondrial respiratory chain, mitochondrial DNA or mitochondria-related apoptotic factors [ 44 ]. In turn, we also had shown that NBIF did not affect the mitochondria membrane potential in astrocytes, except in the cells treated with a doxorubicin + NBIF mix.…”