The effect of mollugin, isolated from the roots of Rubia cordifolia L., on cell viability, apoptosis and adipogenesis in 3T3-L1 preadipocytes was investigated. The inhibitory effect of mollugin (40-60 µM) on cell viability was more significant in differentiated adipocytes than in 3T3-L1 preadipocytes. In 3T3-L1 cells, the cytotoxicity of mollugin was accompanied by apoptotic events including mitochondrial membrane potential (Δψm) loss and activation of caspase-9, -3 and -7, leading to PARP degradation. Although the presence of 20 µM mollugin during induced adipocytic differentiation of 3T3-L1 cells for 6 days failed to affect the cell viability, it could almost completely abrogate the differentiation-associated morphology change and intracellular lipid accumulation. A similar level of inhibition was observed, when 20 µM mollugin was present during the early stage (D0-D2) of the differentiation period. In addition, the expression of C/EBPα, PPARγ1 and PPARγ2 was significantly down-regulated. The presence of 20 µM mollugin during either middle stage (D2-D4) or late stage (D4-D6) of the differentiation period, however, caused the inhibition to a lesser extent. These results indicated that mollugin at high concentrations (40-60 µM) exerted cytotoxicity via inducing apoptosis, whereas mollugin at a low concentration (20 µM) suppressed adipocytic differentiation without exerting cytotoxicity in 3T3-L1 preadipocytes.
"In addition, this plant has been used in traditional Chinese medicine for the treatment of arthritis, dysmenorrheal, hematorrhea, hemostasis, and psoriasis [11, 12]. Among the bioactive components from Rubia cordifolia, mollugin (C17H16O4; methyl 2,2-dimethyl-6-hydroxy-2H-naphtho[1,2-b]pyran-5-carboxylate) has been reported to have antitumor and anti-inflammatory activities, and neuroprotective and apoptotic effects [13–16]. A recent study demonstrated that mollugin induced apoptosis through endoplasmic reticulum stress-mediated activation of c-Jun N-terminal kinase (JNK) and the mitochondria-dependent caspase cascade, regulated by Bcl-xL in human Jurkat T cells . "
[Show abstract][Hide abstract] ABSTRACT: Although previous studies have shown that mollugin, a bioactive phytochemical isolated from Rubia cordifolia L. (Rubiaceae), exhibits antitumor effects, its biological activity in oral cancer has not been reported. We thus investigated the effects and putative mechanism of apoptosis induced by mollugin in human oral squamous cell carcinoma cells (OSCCs). Results show that mollugin induces cell death in a dose-dependent manner in primary and metastatic OSCCs. Mollugin-induced cell death involved apoptosis, characterized by the appearance of nuclear shrinkage, flow cytometric analysis of sub-G1 phase arrest, and annexin V-FITC and propidium iodide staining. Western blot analysis and RT-PCR revealed that mollugin suppressed activation of NF- κ B and NF- κ B-dependent gene products involved in antiapoptosis (Bcl-2 and Bcl-xl), invasion (MMP-9 and ICAM-1), and angiogenesis (FGF-2 and VEGF). Furthermore, mollugin induced the activation of p38, ERK, and JNK and the expression of heme oxygenase-1 (HO-1) and nuclear factor E2-related factor 2 (Nrf2). Mollugin-induced growth inhibition and apoptosis of HO-1 were reversed by an HO-1 inhibitor and Nrf2 siRNA. Collectively, this is the first report to demonstrate the effectiveness of mollugin as a candidate for a chemotherapeutic agent in OSCCs via the upregulation of the HO-1 and Nrf2 pathways and the downregulation of NF- κ B.
"It represents a pivotal signaling protein in the apoptotic cascade. Inhibition of Caspase 9 by a chemical inhibitor mollugin affects adipogenesis [10, 11]. It is alternatively spliced to caspase 9a (apoptotic) and caspase 9b (antiapoptosis) via inclusion of the cassette exons 3, 4, 5, and 6 in caspase 9a (Figure 2(c)). "
[Show abstract][Hide abstract] ABSTRACT: Obesity and its comorbidities affect millions of people. Here, we demonstrate that human preadipocytes are susceptible to programmed cell death (apoptosis) while mature adipocytes are resistant to apoptosis. The molecular mechanisms underlying the phenotype of apoptosis-resistant adipocytes are lesser known. To study the role of apoptosis and define molecular differences in the developmental process of adipogenesis, human preadipocytes were differentiated
to mature adipocytes. Many genes in the apoptosis pathway are alternatively spliced. Our data demonstrates that during differentiation PKC
, Bclx, and Caspase9 switch to their prosurvival splice variants along with an increase in Bcl2 expression when the cells terminally differentiate into mature adipocytes. Next we determined the expression pattern of these genes in obesity. Our data indicated high expression of PKC
VIII in adipose tissue of obese patient in different depots. We demonstrate a shift in the
expression of these splice variants in differentiating preadipocytes derived from obese patients along with a decrease in adipogenesis markers. Hence, the programmed splicing of antiapoptotic proteins is a pivotal switch in differentiation that commits adipocytes to a prosurvival pathway. The expression pattern of these genes is dysregulated in obesity and may contribute to adipose tissue dysfunction.
[Show abstract][Hide abstract] ABSTRACT: Obesity is an increasing world problem that may cause several metabolic complications including insulin resistance, hyperlipidemia, hypertension, and atherosclerosis. Development of therapeutic drugs for obesity has been proven difficult. Current strategies for weight reduction are inhibition of food intake through the central nervous system or blocking the absorption of lipids in the gut. These therapies have many side effects, so new treatments are urgently needed. Fat loss could also be achieved through a decrease in the size and number of adipocytes through apoptosis. Apoptosis is a normal phenomenon of cell death for the purpose of maintaining homeostasis. Induction of apoptosis is a reasonable way to remove adipocytes in obese patients. It is reported that several adipokines and natural products play roles in induction of adipocyte apoptosis. Here we review the recent progress of the roles and mechanisms of adipocyte apoptosis induced by leptin, tumor necrosis factor-α (TNF-α), and natural compounds.
Biochemical and Biophysical Research Communications 12/2011; 417(1):1-4. DOI:10.1016/j.bbrc.2011.11.158 · 2.30 Impact Factor
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