Identification of Crucial Polymethoxyflavones Tangeretin and 3,5,6,7,8,3',4'-Heptamethoxyflavone and Evaluation of Their Contribution to Anticancer Effects of Pericarpium Citri Reticulatae 'Chachi' during Storage.

Pericarpium Citri Reticulatae 'Chachi' (PCR-C), rich in polymethoxyflavones (PMFs), has potential anticancer bioactivity and its quality will be improved during storage. However, the main factors influencing the PCR-C quality during its storage remain unclear. In this study, multivariate analysis was performed to investigate free and bound PMFs of PCR-C during storage. The anticancer effects of purified PCR-C flavonoid extracts (PCR-CF) and the important PMFs were evaluated using A549 cells. The results showed that PCR-C samples exhibited remarkable differences in free PMFs during storage, which fell into three clusters: Cluster 1 included fresh (fresh peel) and PCR-C01 (year 1); Cluster 2 consisted of PCR-C03 (year 3) and PCR-C05 (year 5); and PCR-C10 (year 10) was Cluster 3. 3,5,6,7,8,3',4'-heptamethoxyflavone, tangeretin, and isosinensetin were identified as the most important PMFs distinguishing the various types of PCR-C according to its storage periods. Moreover, PCR-CF inhibited A549 cell proliferation and induced cell cycle arrest at G2/M phase, cell apoptosis, and ROS accumulation, and all anticancer indices had an upward tendency during storage. Additionally, tangeretin and 3,5,6,7,8,3',4'-heptamethoxyflavone exhibited anticancer effects on A549 cells, whereas isosinensetin displayed no anticancer effect, indicating that tangeretin and 3,5,6,7,8,3',4'-heptamethoxyflavone jointly contributed to anticancer activity of PCR-C during storage. PCR-CF and the most important PMFs killed cancer cells (A549 cells) but had no cytotoxicity to normal lung fibroblast cells (MRC-5 cells). Overall, the high quality of long-term stored PCR-C might be due to the anticancer effects of tangeretin and 3,5,6,7,8,3',4'-heptamethoxyflavone.

Aged Pericarpium Citri Reticulatae 'Chachi' Attenuates Oxidative Damage Induced by tert-Butyl Hydroperoxide (t-BHP) in HepG2 Cells.

This study investigated the protective effects of aged Pericarpium Citri Reticulatae 'Chachi' (PCR-C) on tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in HepG2 cells. According to HPLC analysis, PCR-C aged 10 years (PCR-C10) had the highest flavonoids content, especially polymethoxyflavones (PMFs), compared with the fresh peel of Citrus reticulata cv. 'Chachiensis' and PCR-C aged 1, 3, and 5 years. Then, flavonoids-rich PCR-C samples and non-flavonoids-rich PCR-C samples (NF) were prepared by extracting and purifying PCR-C of different aging periods, for further cell experiments. Pretreatment with flavonoids-rich PCR-C samples (particularly PCR-C10) considerably reversed t-BHP-induced oxidative damage in HepG2 cells by improving cell viability, increasing SOD activity and GSH levels and reducing the overproduction of ROS and MDA. Correlation analysis further indicated that the accumulation of PMFs, mainly 5,6,7,4'-tetramethoxyflavone and nobiletin, was the main reason that PCR-C10 maintained the redox balance in HepG2 cells. These findings provided direct evidence for the cellular antioxidant activity of aged PCR-C and a guide for PCR-C's classification, authentication and rational use.

Curcumol inhibits colorectal cancer proliferation by targeting miR-21 and modulated PTEN/PI3K/Akt pathways.

AIMS: The purpose of this study was to demonstrate how curcumol affected the expression of miR-21 and whether its effects on miR-21 was associated with the activation of PTEN/PI3K/Akt pathways in CRC cells. MAIN METHODS: MTT and xenograft assay were used to examine how curcumol inhibits colorectal cancer (CRC) cells' growth. Q-PCR and western blot analysis were employed to test the role of miR-21 in the inhibition of curcumol on proliferation and PTEN/PI3K/Akt pathways of CRC cells. KEY FINDINGS: We found that curcumol effectively inhibited CRC cells from proliferating via the PTEN/PI3K/Akt pathways and reduced expression of miR-21 both in vitro and in vivo. miR-21 mimics were found to decrease the protein level of PTEN and increase the expression of PI3K, phospho-Akt (p-Akt) and NF-κB, while miR-21 sponge (miR-21-SP) enhanced the expression of PTEN and reduced the activity of PI3K, Akt and NF-κB. Furthermore, miR-21-SP strengthened the role of curcumol in up-regulating PTEN and inhibiting PI3K/Akt pathways, but miR-21 reversed the effect of curcumol on the PTEN/PI3K/Akt pathways. SIGNIFICANCE: Our research demonstrated that curcumol reduced the proliferation of CRC cells through PTEN/PI3K/Akt by targeting miR-21 and miR-21 could be a target molecule of curcumol for CRC treatment.

In vitro study of anti-ER positive breast cancer effect and mechanism of 1,2,3,4-6-pentyl-O-galloyl-beta-d-glucose (PGG).

Breast cancer is one of the most common malignancies and the leading cause of women's death, most of breast cancers are estrogen receptor-positive (ER+) breast cancer which can develop into advanced stage from early stage with treatment resistance. The purpose of this study was to investigate anti-ER+ breast cancer effects of 1,2,3,4,6-penta-O-galloyl-ß-d-glucose (PGG) and its possible mechanisms. Cell viability was analyzed by MTT assay. The cell cycle distribution and apoptosis were detected by Flow cytometry. The expressions of cell proliferation- and apoptosis-related proteins were determined by western blot and immunofluorescence staining. The results showed PGG induced cytotoxicity and decreased viability of ER+ breast cancer T-47D and BT-474 cells. Flow cytometry analysis revealed that cell cycle was blocked in S phase at lower dose (25 µM PGG), and G1 phase at higher dose (50 or 75 µM PGG). One of the underlying mechanisms of the anti-cancer effect exerted by PGG was owed to inhibition of the expression of HURP, an up-regulated protein in human hepatocellular carcinoma which is closely related to tumor proliferation, invasion and metastasis. PGG affected cell cycle- or apoptosis-related proteins such as cyclin D1, Bcl-2 and Bax. These data suggest that PGG exerts anti-ER+ breast cancer effects. In this sense, our study provides new alternative therapies to treat breast cancer.

Inhibition of chemotherapy-induced apoptosis of testicular cells by squid ink polysaccharide.

The aim of this study was to determine the mechanisms driving the protective effects of squid ink polysaccharide (SIP) against cyclophosphamide (CP)-induced testicular damage, focusing on germ cells. In the testes of mice exposed to CP and/or SIP, the present study examined the levels of reactive oxygen species (ROS) and malondialdehyde, activity of superoxide dismutase levels, protein expression levels of B-cell lymphoma 2 (Bcl2), Bcl2-associated X protein (Bax), and total Caspase 3, activation of p-p38 and p-Akt proteins, and tissue morphology. The findings indicated that CP induced ROS production and oxidative stress, resulting in testicular damage. However, under administration of SIP, oxidative stress was impaired and the testicular toxicity induced by CP was weakened, which implied that SIP may have an important role in preventing chemotherapeutic damage to the male reproductive system via promoting antioxidant ability. Furthermore, the altered expression levels, including the upregulation of Bax and Caspase 3, downregulation of Bcl-2 and the increased Bax/Bcl-2 ratio, indicated that apoptosis occurred in CP exposed testes of mice; however, the alterations were reversed in mice treated with SIP. Moreover, in CP-exposed testes, p38 and Akt proteins were significantly phosphorylated (P<0.05), whereas in the testes of mice co-treated with SIP and CP, phosphorylation of the two proteins was inhibited, demonstrating that the two signalling pathways participated in the regulative processes of the deleterious effects caused by CP, and the preventive effects SIP mediated.

Inhibition of acrolein-induced autophagy and apoptosis by a glycosaminoglycan from Sepia esculenta ink in mouse Leydig cells.

In our recent reports, a squid ink polysaccharide (SIP) was found having preventive activity against cyclophosphamide induced damage in mouse testis and ovary. Here we further reveal the regulative mechanism of SIP against chemical toxicity on testis. Leydig cells exposed to acrolein (ACR) underwent apoptosis at 12h and 24h. Before apoptosis, cells occurred autophagy that was confirmed by high autophagic rate and Beclin-1 protein content at 3h. PI3K/Akt and p38 MAPK signal pathways involved in the regulatory mechanisms. These outcomes of ACR were recovered completely by SIP, which was demonstrated by attenuated disruption of redox equilibrium and increased testosterone production, through suppressing ACR-caused autophagy and apoptosis regulated by PI3K/Akt and p38 MAPK signal pathways in Leydig cells. Summarily, autophagy occurred before apoptosis caused by ACR-activated p38 MAPK and PI3K/Akt pathways were blocked by SIP, resulting in survival and functional maintenance of Leydig cells.

Preventive Effects of a Novel Polysaccharide from Sepia esculenta Ink on Ovarian Failure and Its Action Mechanisms in Cyclophosphamide-Treated Mice.

On the basis of our findings about chemo-preventive roles of squid ink polysaccharide and the well-known toxicity of cyclophosphamide (CP) on female gonad, this research investigated the protective effects of a novel polysaccharide from Sepia esculenta ink (SEP) on the ovarian failure resulting from CP, as well as the action mechanisms underpinning this. The results indicated that CP destroyed the ovaries of mice which caused depletion of various follicles, and led to a reduction in estradiol content, increases in FSH and LH contents in sera, decreases in ovary and uterus masses and their relative mass ratios, disruption of the ultrastructure of granulosa cells, as well as induction of apoptosis and autophagy via p38 MAPK and PI3K/Akt signaling pathways. The phenomenon resulted in ovarian failure. However, SEP exposure altered the negative effects completely. The data indicated that SEP can effectively prevent ovarian failure CP caused in mice by inhibiting the p38 MAPK signaling pathway and activating the PI3K/Akt signaling pathway as regulated by CP. SEP was a novel polysaccharide from Sepia esculenta ink with a unique primary structure mainly composed of GalN and Ara that accounted for almost half of all monosaccharides: their ratio was nearly one-to-one. Besides, the polysaccharide contained a small number of Fuc and tiny amounts of Man, GlcN, GlcA, and GalA.

Polysaccharide from Sepia esculenta ink and cisplatin inhibit synergistically proliferation and metastasis of triple-negative breast cancer MDA-MB-231 cells.

OBJECTIVES: This paper aims to investigate synergistic inhibition of polysaccharide from Sepia esculenta ink (SIP), a newly isolated marine polysaccharide in our laboratory, on breast cancer MDA-MB-231 cells exposed to cisplatin. MATERIALS AND METHODS: Cell viability of MDA-MB-231 cells was determined by CCK 8 assay. Median-effect concentration was analyzed using Chou-Talalay method that was also subjected to determine cell inhibition ratio and combined index, as well as interaction between SIP and cisplatin. Proliferation and migration abilities were detected with plate colony formation assay and cell wound scratch assay, respectively. Expression of MMP-2 and MMP-9 proteins was measured with Western blot assay. RESULTS: Data showed that SIP not only suppressed proliferation and migration of MDA-MB-231 cells, and expression of MMP-2 and MMP-9 proteins, also promoted inhibition of cisplatin on proliferation, migration and MMPs expression of MDA-MB-231 cells, which indicates synergy inhibition of drug combination of SIP and cisplatin on breast cancer cells. The median-effect concentrations of cisplatin and SIP were 4.9 and 1659.6 µg/ml, respectively. Whereas the concentration of combination drug was 158.5 µg/ml. The data indicated that drug combination can decrease dosages of the two single agents, especially the usual dosage of cisplatin. CONCLUSION: This research demonstrated that SIP repressed proliferation and metastasis of MDA-MB-231 cells and promoted anticancer effect of cisplatin on the breast cancer cells. The data suggested that SIP is a potential natural drug that can be used as an auxiliary medicine alongside chemotherapy in treating breast cancer.

Squid ink polysaccharide reduces cyclophosphamide-induced testicular damage via Nrf2/ARE activation pathway in mice.

OBJECTIVES: Cyclophosphamide (CP) toxicity on testis was hampered by squid ink polysaccharide (SIP) via restoration of antioxidant ability in our previous investigations. This study investigated roles of Nrf2/ARE signal pathway in testis of treated mice. MATERIALS AND METHODS: Male Kunming mice were employed to undergo treatment with SIP and/or CP. Protein levels of Nrf2, keap-1, histone deacetylase 2 (HDAC2), quinone oxidoreductase 1 (NQO-1), and heme oxygenase 1 (HO-1) and phosphorylation level of protein kinase C (PKC) in testis were evaluated by Western blotting. RESULTS: Data showed that SIP elevated expressions of NQO-1 and HO-1 genes, two downstream target molecules of Nrf2, via activating Nrf2 to play preventive roles on CP-treated testis, and further discovered that upstream regulators of Nrf2, keap-1, HDAC2, and PKC, were concerned with the regulation of Nrf2. CONCLUSION: These results suggest that SIP could effectively weaken CP-associated testicular damage via Nrf2/ARE signal pathway.