Pterostilbene modulates the suppression of multidrug resistance protein�1 and triggers autophagic and apoptotic mechanisms in cisplatin-resistant human oral cancer CAR cells via AKT signaling

Abstract

Pterostilbene is a natural polyphenolic compound that is primarily found in fruits, such as blueberries and has a similar structure to resveratrol. Pterostilbene exhibits antioxidant, anti-inflammatory and antitumor activity but the effects of pterostilbene on drug-resistant oral cancer cells and its underlying mechanisms of action have not yet been explored. Therefore, the present study was performed to clarify the anticancer effects of pterostilbene on cisplatin-resistant human oral cancer CAR cells. The results demonstrated that CAR cells exhibited marked shrinkage, cell membrane breakage and autophagic vacuole formation following treatment with pterostilbene. Pterostilbene also effectively inhibited cell viability and suppressed cell confluence in a time- and concentration-dependent manner. Probing with acridine orange, monodansylcadaverine and LysoTracker Red demonstrated that the number of acidic vesicular organelles was increased, indicating increased autophagy. Furthermore, Heochst 33342 staining determined that DNA condensation, a characteristic of apoptosis, was enhanced following treatment with pterostilbene. Furthermore, pterostilbene upregulated mRNA levels of LC3-II and Atg12, as well as the expression of Atgs/Beclin-1/LC3-associated signaling, suggesting that it enhances autophagy. The autophagy inhibitors 3-methyladenine and chloroquine were used to confirm that pterostilbene induces autophagy. It was also determined that pterostilbene triggered caspase-dependent apoptosis by directly testing DNA breakage and using the pan-caspase inhibitor carbobenzoxyvalyl-alanyl-aspartyl fluoromethyl ketone. The results demonstrated that pterostilbene mediates the apoptosis of CAR cells via the intrinsic apoptotic cascade. In addition, pterostilbene inhibited MDR1 expression and the phosphorylation of AKT on the Ser473 site in CAR cells. Therefore, pterostilbene may elicit an oral anticancer response in drug-resistant cells and may be used as a chemotherapeutic adjuvant to treat patients with oral cancer.

Caspase‑dependent apoptotic death by gadolinium chloride (GdCl3) via reactive oxygen species production and MAPK signaling in rat C6 glioma cells

“…Induction of tumor cell apoptosis is one of the best strategies for treating glioma and multiple types of cancers (27,28). Apoptotic death can be activated by three main pathways (17,29). The extrinsic pathway is triggered through binding of extrinsic signals to death receptors, which leads to activation of caspase-8 (29,30).…”

“…C6 cells (5x10 6 cells/75T flask) were incubated with the presence and absence of 0, 50, 100 and 200 µM of GdCl 3 for 24 h. After cells were lysed, total protein (40 µg) was separated using 10% SDS-polyacrylamide gel electrophoresis (PAGE) and transferred onto polyvinylidene difluoride (PVDF) membranes (Immobilon-P Transfer membrane; Merck Millipore, Darmstadt, Germany). As previously described (17,18), the membranes were probed with primary antibodies against caspase-3, caspase-8, caspase-9, cytochrome c, Bax, Bcl-2, p-ERK, ERK, p-JNK, JNK, p-p38, p38, (all 1:1,000 dilution) and β-actin (1:5,000 dilution). The membranes were then incubated with goat anti-rabbit IgG-HRP or goat anti-mouse IgG-HRP linked antibodies (1:10,000 dilution) for 1 h at room temperature.…”

Development of xenograft oral squamous cell carcinoma mouse model

“…12,13,14 Bununla birlikte, güncel tedaviler kapsamında, kematerapötik ajanlara gelişen direnci aşmak ve yine bu ajanlara bağlı yan etkileri azaltmak için kombine ilaç tedavisi ve adjuvan tedavi yöntemlerinin geliştirilmesi de bulunmaktadır. 15 Gerek güncel tedavilerin geliştirilmesine, gerekse de kullanımda olan ve yeni geliştirilen ilaçların denenmesine yönelik hastalık modellerinin oluşturulması çok değerlidir. Bu nedenle çalışmamızın amacı, hastalık tedavisine destek sağlayacak ksenograft oral YHK fare modelinin geliştirilmesi olmuştur.…”

Pterostilbene Inhibits Human Renal Cell Carcinoma Cells Growth and Induces DNA Damage

“…Previous studies have found that natural products and phytochemicals in plants have certain curative effects on various types of cancers, including anticancer activity and low toxicity. Pterostilbene (PTE), a natural polyphenolic compound, primarily found in fruits, such as blueberries, grapes, and tree wood, 6) has received a great deal of attention for its potent antioxidant and anti-inflammatory properties 7) ; and anticancer effect on a wide range of cancers, including prostate, bladder, colorectal, and oral cancer and so on. 8) But the molecular mechanism is still unclear.…”