Proanthocyanidin Polymer-Rich Fraction of Stryphnodendron adstringens Promotes in Vitro and in Vivo Cancer Cell Death via Oxidative Stress

Abstract

Cervical cancer is the fourth most common cancer that affects women, mainly through human papilloma virus (HPV) infection with high-risk HPV16 and HPV18. The present study investigated the in vitro anticancer activity and mechanism of action of a proanthocyanidin polymer-rich fraction of Stryphnodendron adstringens (F2) in cervical cancer cell lines, including HeLa (HPV18-positive), SiHa (HPV16-positive), and C33A (HPV-negative) cells, and also evaluated in vivo anticancer activity. In vitro, cell viability was determined by the MTT assay. Cell migration was determined by the wound healing assay. The mechanism of action was investigated by performing ultrastructural analysis and evaluating reactive oxygen species (ROS) production, mitochondrial metabolism, lipoperoxidation, BCL-2 family expression, caspase expression, and DNA and cell membrane integrity. In vivo activity was evaluated using the murine Ehrlich solid tumor model. F2 time- and dose-dependently reduced cell viability and significantly inhibited the migration of cervical cancer cells. HeLa and SiHa cells treated with F2 (IC50) exhibited intense oxidative stress (i.e., increase in ROS and decrease in antioxidant species) and mitochondrial damage (i.e., mitochondrial membrane potential depolarization and a reduction of intracellular levels of adenosine triphosphate). Increases in the Bax/BCL-2 ratio and caspase 9 and caspase 3 expression, were observed, with DNA damage that was sufficient to trigger mitochondria-dependent apoptosis. Cell membrane disruption was observed in C33A cells (IC50 and IC90) and HeLa and SiHa cells (IC90), indicating progress to late apoptosis/necrosis. The inhibition of ROS production by N-acetylcysteine significantly suppressed oxidative stress in all three cell lines. In vivo, F2 significantly reduced tumor volume and weight of the Ehrlich solid tumor, and significantly increased lipoperoxidation, indicating that F2 also induces oxidative stress in the in vivo model. These findings indicate that the proanthocyanidin polymer-rich fraction of S. adstringens may be a potential chemotherapeutic candidate for cancer treatment.

Characterization and Antioxidant Activities of Yellow Strain Flammulina velutipes (Jinhua Mushroom) Polysaccharides and Their Effects on ROS Content in L929 Cell

“…All of the images were converted to grayscale images and then inverted and calibrated while using Image J. The mean fluorescence intensities were calculated as mean gray values that were derived from the sum of the gray values of all the pixels in the selection divided by the number of pixels [28,29,30].…”

Bioprospecting of Natural Compounds from Brazilian Cerrado Biome Plants in Human Cervical Cancer Cell Lines

“…Recently, a leaf fraction of Stryphnodendron adstringens containing gallic acid, procyanidin dimer B1, and (−)-epicatechin-3-O-gallate showed antioxidant activity and cytotoxicity toward human breast cancer cell lines [ 42 ]. A proanthocyanidin polymer-rich fraction from stem bark promoted in vitro and in vivo cancer cell death via oxidative stress in the cervical cancer model [ 43 ].…”

Evidências sobre as propriedades do extrato de Stryphnodendron adstringens (Mart.) Coville (Barbatimão) para a prática clínica

“…(Filho, Ferreira, & Gouvêa, 2011) In other study, a model experimental to breast cancer and antitumoral potential concluded that the Barbatimão fractions decreased cancer cell viability as well as cell rounding-up, shrinkage, and nuclear condensation reduction of cell diameter and length and induced apoptosis (Sabino et al, 2017). A recent study demonstrated the in vitro and in vivo anticancer activity of a proanthocyanidin polymer-rich fraction of Stryphnodendron adstringens in cervical cancer cell lines HPV-positive (16 and 18), concluding that these cells treated with Barbatimão showed particular increase of free radicals and decrease of antioxidant species, mitochondrial membrane depolarization, progression to apoptosis as well as significant reduction of volume and induced weight tumoral (Kaplum et al, 2018).…”