Anticancer Effects of Morusin in Prostate Cancer via Inhibition of Akt/mTOR Signaling Pathway.

Prostate cancer (PCa) is the second most prevalent cancer in men worldwide. The majority of PCa incidences eventually progress to castration-resistant PCa (CRPC), thereby establishing an urgent need for new effective therapeutic strategies. This study aims to examine the effects of morusin, a prenylated flavonoid isolated from Morus alba L., on PCa progression and identify the regulatory mechanism of morusin. Cell growth, cell migration and invasion, and the expression of EMT markers were examined. Cycle progression and cell apoptosis were examined using flow cytometry and a TUNEL assay, while transcriptome analysis was performed using RNA-seq with results being further validated using real-time PCR and western blot. A xenograft PCa model was used to examine tumor growth. Our experimental results indicated that morusin significantly attenuated the growth of PC-3 and 22Rv1 human PCa cells; moreover, morusin significantly suppressed TGF-[Formula: see text]-induced cell migration and invasion and inhibited EMT in PC-3 and 22Rv1 cells. Significantly, morusin treatment caused cell cycle arrest at the G2/M phase and induced cell apoptosis in PC-3 and 22Rv1 cells. Morusin also attenuated tumor growth in a xenograft murine model. The results of RNA-seq indicated that morusin regulated PCa cells through the Akt/mTOR signaling pathway, while our western blot results confirmed that morusin suppressed phosphorylation of AKT, mTOR, p70S6K, and downregulation of the expression of Raptor and Rictor in vitro and in vivo. These results suggest that morusin has antitumor activities on regulating PCa progression, including migration, invasion, and formation of metastasis, and might be a potential drug for CRPC treatment.

Induction of apoptosis and ganoderic acid biosynthesis by cAMP signaling in Ganoderma lucidum.

Apoptosis is an essential physiological process that controls many important biological functions. However, apoptosis signaling in relation to secondary metabolite biosynthesis in plants and fungi remains a mystery. The fungus Ganoderma lucidum is a popular herbal medicine worldwide, but the biosynthetic regulation of its active ingredients (ganoderic acids, GAs) is poorly understood. We investigated the role of 3',5'-cyclic adenosine monophosphate (cAMP) signaling in fungal apoptosis and GA biosynthesis in G. lucidum. Two phosphodiesterase inhibitors (caffeine and 3-isobutyl-1-methylxanthine, IBMX) and an adenylate cyclase activator (sodium fluoride, NaF) were used to increase intracellular cAMP levels. Fungal apoptosis was identified by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay and a condensed nuclear morphology. Our results showed that GA production and fungal apoptosis were induced when the mycelium was treated with NaF, caffeine, or cAMP/IBMX. Downregulation of squalene synthase and lanosterol synthase gene expression by cAMP was detected in the presence of these chemicals, which indicates that these two genes are not critical for GA induction. Transcriptome analysis indicated that mitochondria might play an important role in cAMP-induced apoptosis and GA biosynthesis. To the best of our knowledge, this is the first report to reveal that cAMP signaling induces apoptosis and secondary metabolite production in fungi.

Denbinobin, a phenanthrene from Dendrobium nobile, impairs prostate cancer migration by inhibiting Rac1 activity.

Prostate cancer is the most prevalent type of cancer in the United States. The most common site of prostate cancer metastasis is bone. CXCL12 is preferentially expressed in bone and is targeted by prostate cancer cells, which over-express the receptor for CXCL12, CXCR4. In response to CXCL12 stimulation, Rac1, a GTPase, along with its effectors, regulates actin polymerization to form lamellipodia, which is a critical event for cell migration. Cortactin, an actin-binding protein, is recruited to the lamellipodia and is phosphorylated at tyrosine residues. The phosphorylated cortactin is also involved in cell migration. The inhibition of Rac1 activity using a dominant negative Rac1 impairs lamellipodial protrusion as well as cortactin translocation and cortactin phosphorylation. Denbinobin, a substance extracted from Dendrobium nobile, has anticancer effects in many cancer cell lines. Whether denbinobin can inhibit prostate cancer cell migration is not clear. Here, we report that denbinobin inhibited Rac1 activity. The inhibition of Rac1 activity prevented lamellipodial formation. Cortactin phosphorylation and translocation to the lamellipodia were also impaired, and PC3 cells were unable to migrate. These results indicate that denbinobin prevents CXCL12-induced PC3 cell migration by inhibiting Rac1 activity.

The first bis-retrochalcone from Fissistigma latifolium.

Two novel chalconoids, [3-3'']bi-2-hydroxy-4,5,6-trimethoxydihydrochalcone (1) and 4,6-dimethoxy-2,5-quinodihydrochalcone (2), and twelve known compounds were isolated from the methanolic extract of Fissistigma latifolium (Dun.) Merr. The structures of all compounds were determined by spectroscopic methods. Of these, compounds 1, 2, and 2-hydroxy-4,5,6-trimethoxydihydrochalcone (10) belong to an uncommon group of chalconoids, the retrochalcones. Compound 1 is the first bis-retrochalcone to be reported, and compound 2 is a quinoretrochalcone. Furthermore, 2 showed activity against the MDA-MB-231 human breast cancer cell line with an IC (50) value of 7.1 µM.

Proteomics displays cytoskeletal proteins and chaperones involvement in Hedyotis corymbosa-induced photokilling in skin cancer cells.

Photodynamic therapy was found to be an effective therapy for local malignant tumors. This study demonstrated that 80 µg/ml Hedyotis corymbosa extracts with 0.8 J/cm(2) fluence dose caused M21 skin cancer cell death. Photoactivated H. corymbosa-induced M21 cell death is a typical apoptosis that is accompanied by nuclear condensation, externalization of phosphatidylserine and the changes in protein expression of apoptosis-related proteins, such as Bcl-2 and caspase family members. This study applied 2D electrophoresis to analyse the proteins involved in the photoactivated H. corymbosa-induced M21 cell apoptosis. We found 12 proteins to be markedly changed. According to the results of protein sequence analysis of these altered protein spots, we identified that the expression of cytoskeletal proteins and chaperones were involved in the photoactivated H. corymbosa-induced M21 cell apoptosis. We further demonstrated that photoactivated H. corymbosa caused a significant effect on the cytoskeleton distribution and mitochondrial activity in M21 cells. Based on the above findings, this study characterized the effects and mechanisms of the photoactivated H. corymbosa-induced apoptosis in M21 skin cancer cells.

Rottlerin Inhibits Lonicera japonica-Induced Photokilling in Human Lung Cancer Cells through Cytoskeleton-Related Signaling Cascade.

This study demonstrated that many apoptotic signaling pathways, such as Rho family, PKC family, MAP kinase family, and mitochondria-mediated apoptotic pathway, were triggered by Lonicera japonica extracts and irradiation in CH27 cells. Rottlerin, a PKCδ -selective inhibitor, reversed the photoactivated Lonicera japonica extract-induced decrease in PKCδ protein expression and change in cell morphology in this study. In addition, rottlerin inhibited the photoactivated Lonicera japonica-induced decrease in protein expression of Ras, ERK, p38, PKCα, and PKCε, which are the kinases of prosurvival signaling pathway. We also demonstrated that pretreatment with rottlerin prevented actin microfilaments and microtubules from damage during the photoactivated Lonicera japonica-induced CH27 cell death. Furthermore, the promotion of the cytoskeleton-related signaling cascade following rottlerin by upregulation of cytoskeleton-related mediators (p38, HSP27, FAK, paxillin, and tubulin) and molecules of downstream of F-actin (mitochondria-mediated apoptosis pathway) reduces CH27 cell death, indicating that cytoskeleton is the potential target in the photoactivated Lonicera japonicaextract-induced photokilling of CH27 cells.