P-Hydroxycinnamaldehyde Induces B16-F1 Melanoma Cell Differentiation via the RhoA-MAPK Signaling Pathway.

BACKGROUND/AIMS: Due to its antitumor and gastroprotective properties, cochinchina momordica seed (CMS), has been widely used to treat cancer patients in Asia. Our previous reports have shown that CMS is able to induce the differentiation of B16-F1 melanoma cells. However, its functional component and mechanism remain unclear and are addressed in this study. METHODS AND RESULTS: CMSP (p-hydroxycinnamaldehyde isolated from CMS) inhibited the proliferation, migration and invasiveness of B16-F1 cells both in vivo and in vitro. CMSP also induced the differentiation of B16-F1 cells, as characterized by dendrite-like outgrowth, increased melanogenesis and enhanced tyrosinase activity. Furthermore, CMSP treatment reduced the level of malignant markers of melanoma, specifically S-100B and melanoma-derived growth regulatory protein precursor (MIA), in a concentration-dependent manner. According to a western blot analysis, B16-F1 cells treated with CMSP exhibited a sustained increase in p-P38 and decreased activities of ERK and JNK. Our data further indicated that the downregulation of GTP-RhoA, which was mediated by increased cAMP release, was involved in CMSP-induced changes in MAPK, while LPA (Lysophosphatidic acid) partially reversed CMSP-induced B16 cell differentiation. CONCLUSION: These results demonstrated that CMSP-induced differentiation of B16F1 cells may occur through the RhoA-MAPK axis, which suggests a new potential strategy for melanoma treatment.

[Coumarins of Anemone raddeana Regel and their biological activity].

To study the coumarins of Anemone raddeana Regel, the compounds were separated by silica gel column chromatography and HPLC. Their structures were identified by their physicochemical property and spectral analysis. Two new compounds were isolated and identified as 4, 7-dimethoxyl-5-methyl-6-hydroxy coumarin (1) and 4, 7-dimethoxyl-5-formyl-6-hydroxycoumarin (2). The bioassays indicated that compounds 1 and 2 could significantly inhibit the proliferation of cancer cell, and showed the agonist effect on the transactivity of retinoic acid receptor-alpha (RARalpha). In addition, the two compounds had inhibitory effect against human leukocyte elastase (HLE).

[New homoisoflavanones from Polygonatum odoratum (Mill.) Druce].

To study chemical constituents of Polygonatum odoratum (Mill.) Druce, the compounds were separated with column chromatography and HPLC. On the basis of physicochemical properties and spectral data, their structures were confirmed. Nine compounds were isolated and identified as 5,7-dihydroxy-6-methoxyl-8-methyl-3-(2',4'-dihydroxybenzyl)chroman-4-one (1), 5,7-dihydroxy-6-methyl-3-(2',4'-dihydroxybenzyl)chroman-4-one (2), 5,7-dihydroxy-6-methoxyl-8-methyl-3-(4'-methoxybenzyl)chroman-4-one (3), disporopsin (4), chrysoeriol (5), 5,4'-dihydroxy-7-methoxy-6-methylflavone (6), N-trans-feruloyltyramine (7), N-trans-feruloyloctopamine (8), and (+)-syringaresinol (9). Compounds 1-3 are new homoisoflavanones. Compounds 4-9 are isolated from this plant for the first time.

An ester extract of Cochinchina momordica seeds induces differentiation of melanoma B16 F1 cells via MAPKs signaling.

Cochinchina momordica seeds (CMS) have been widely used due to antitumor activity by Mongolian tribes of China. However, the details of the underlying mechanisms remain unknown. In the present study, we found that an EtOAc (ethyl ester) extract of CMS (CMSEE) induced differentiation and caused growth inhibition of melanoma B16 F1 cells. CMSEE at the concentration of 5-200 µg/ml exhibited strongest anti-proliferative effects on B16 F1 cells among other CMS fractions (water or petroleum ether). Moreover, CMSEE induced melanoma B16 F1 cell differentiation, characterized by dendrite-like outgrowth, increasing melanogenesis production, as well as enhancing tyrosinase activity. Western blot analysis showed that sustained phosphorylation of p38 MAP accompanied by decrease in ERK1/2 and JNK dephosphorylation were involved in CMSEE-induced B16 F1 cell differentiation. Notably, 6 compounds that were isolated and identified may be responsible for inducing differentiation of CMSEE. These results indicated that CMSEE contributes to the differentiation of B16 F1 cells through modulating MAPKs activity, which may throw some light on the development of potentially therapeutic strategies for melanoma treatment.

Periplocin from Cortex periplocae inhibits cell growth and down-regulates survivin and c-myc expression in colon cancer in vitro and in vivo via beta-catenin/TCF signaling.

Cancer of the colon and rectum is the third most commonly diagnosed cancer and accounts for approximately 10% of all cancer-related deaths. Although surgical resection or radiotherapy are potentially curative for localized disease, advanced colon cancer is currently associated with poor prognosis. Therefore, the development of a new and effective chemotherapeutic agent is required to target critical pathways to induce responsiveness of colon cancer cells to death signals. Dysregulation of the beta-catenin/TCF pathway plays a central role in early activities of colorectal carcinogenesis. In this study, human colon cancer SW480 cells were used to investigate the effect of CPP (periplocin from Cortex periplocae) on the modulation of the beta-catenin/TCF signaling pathway. Our research results showed that CPP caused a dose- and time-dependent inhibition of cell growth as assessed by MTT assay and an induction in apoptosis as measured by flow cytometry and transmission electron microscopy. Furthermore, the CPP- treated cells were characterized by a decreased expression of beta-catenin protein in the total cell lysates and cytosolic and nuclear extracts. This expression alleviates the binding activity of T-cell factor (Tcf) complexes to its specific DNA-binding sites. Thus, the protein expression of the downstream elements survivin and c-myc was down-regulated. To determine the precise inhibitory mechanisms involved, further in-depth in vivo studies of CPP are warranted. In conclusion, our data suggest that CPP wields a multi-prong strategy to target the beta-catenin/Tcf signaling pathway, leading to the induction of apoptosis and inhibition of growth of colon cancer cells in vitro and in vivo. Therefore, CPP may become a potential agent against colon cancer.