Cancer: Hepatocellular carcinoma, colorectal, liver
Action: Radio-protective, ameliorated myelosuppression, MDR
Radio-protective
The radio-protective effect of paeoniflorin (PF), a main bioactive component in the traditional Chinese herb peony, on irradiated thymocytes and the possible mechanisms of protection have been investigated. Ionizing radiation can induce DNA damage and cell death by generating reactive oxygen species (ROS).
It was found 60Co γ-ray irradiation increased cell death and DNA fragmentation in a dose-dependent manner while increasing intracellular ROS. Pre-treatment of thymocytes with PF (50–200 µg/ml) reversed this tendency and attenuated irradiation-induced ROS generation. Hydroxyl-scavenging action of PF in vitro was detected through electron spin resonance assay. Several anti-apoptotic characteristics of PF, including the ability to diminish cytosolic Ca2+ concentration, inhibit caspase-3 activation, and up-regulate Bcl-2 and down-regulate Bax in 4 Gy-irradiated thymocytes, were determined.
Extracellular regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38 kinase, were activated by 4 Gy irradiation, with their activation partly blocked by pre-treatment of cells with PF. The presence of ERK inhibitor PD98059, JNK inhibitor SP600125 and p38 inhibitor SB203580 decreased cell death in 4 Gy-irradiated thymocytes. These results suggest PF protects thymocytes against irradiation-induced cell damage by scavenging ROS and attenuating the activation of the mitogen-activated protein kinases (Li et al., 2007).
Liver Cancer
Prostaglandin E2 (PGE2) has been shown to play an important role in tumor development and progression. PGE2 mediates its biological activity by binding any one of four prostanoid receptors (EP1 through EP4). Paeoniflorin, a monoterpene glycoside, significantly inhibited the proliferation of HepG2 and SMMC-7721 cells stimulated by butaprost at multiple time points (24, 48, and 72 hours). Paeoniflorin induced apoptosis in HepG2 and SMMC-7721 cells, which was quantified by annexin-V and propidium iodide staining. Our results indicate that the expression of the EP2 receptor and Bcl-2 was significantly increased, whereas that of Bax and cleaved caspase-3 was decreased in HepG2 and SMMC-7721 cells.
Paeoniflorin, which may be a promising agent in the treatment of liver cancer, induced apoptosis in hepatocellular carcinoma cells by down-regulating EP2 expression and also increased the Bax-to-Bcl-2 ratio, thus up-regulating the activation of caspase-3 (Hu et al., 2013).
Colorectal Cancer
Results showed that positive cells of Proliferating Cell Nuclear Antigen (PCNA) in paeoniflorin (PF) and docetaxel-treated group was decreased to 30% and 15% respectively, compared with control group of tumors. But apoptosis cells in docetaxel treated groups studied by TUNEL is increased to 40 ± 1.2% and 30 ± 1.5% respectively, compared with 24 ± 2.3% in negative control. Furthermore, the efficiency of tumor-bearing mice treated by PF was superior to docetaxel in vivo. Overall, PF may be an effective chemo-preventive agent against colorectal cancer HT29 (Wang et al., 2012).
Ameliorates Myelosuppression
The administration of paeoniflorin and albiflorin (CPA) extracted from Paeonia radix, significantly ameliorated myelosuppression in all cases. For the X-ray irradiated mice and the chemotherapy treated mice and rabbits, high dosages of CPA resulted in the recovery of, respectively, 94.4%, 95.3% and 97.7% of hemoglobin content; 67.7%, 92.0% and 94.3% of platelet numbers; 26.8%, 137.1% and 107.3% of white blood cell counts; as well as a reversal in the reduction of peripheral differential white blood cell counts.
There was also a recovery of 50.9%, 146.1% and 92.3%, respectively, in the animals' relative spleen weight. Additionally, a recovery of 35.7% and 87.2% respectively in the number of bone marrow nucleated cells was observed in the radio- and chemo -therapy-treated mice. Bone marrow white blood cell counts also resumed to normal levels (Xu et al., 2011).
MDR
Studies have shown that NF-κB activation may play an essential role in the development of chemotherapy resistance in carcinoma cells. Paeonißorin, a principal bioactive component of the root of Paeonia lactißora, has been reported to exhibit various pharmacological effects. In the present study, Fanh et al. (2012) reported for the first time that paeoniflorin at non-toxic concentrations may effectively modulate multi-drug resistance (MDR) of the human gastric cancer cell line SGC7901/vincristine (VCR) via the inhibition of NF-κB activation and, at least partly, by subsequently down-regulating its target genes MDR1, BCL-XL and BCL-2.
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