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Estrogen-related receptor γ (ERRγ), a member of the orphan nuclear receptor family, is a key mediator in cellular metabolic processes and energy homeostasis. Therefore, ERRγ has become an attractive target for treating diverse metabolic disorders. We recently reported that ERRγ acts as a negative regulator of osteoclastogenesis induced by receptor activator of nuclear factor-κB ligand (RANKL). In the present study, we explored the effects of an ERRγ-specific modulator, GSK5182, on ERRγ-regulated osteoclast differentiation and survival. Interestingly, GSK5182 increased ERRγ protein levels much as does GSK4716, which is an ERRγ agonist. GSK5182 inhibited osteoclast generation from bone-marrow-derived macrophages without affecting cytotoxicity. GSK5182 also attenuated RANKL-mediated expression of c-Fos and nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), pivotal transcription factors for osteoclastogenesis. Arrested osteoclast differentiation was associated with reduced RANK expression, but not with the M-CSF receptor, c-Fms. GSK5182 strongly blocked the phosphorylation of IκBα, c-Jun N-terminal kinase, and extracellular signal-regulated kinase in response to RANKL. GSK5182 also suppressed NF-κB promoter activity in a dose-dependent manner. In addition to osteoclastogenesis, GSK5182 accelerated osteoclast apoptosis by caspase-3 activation. Together, these results suggest that GSK5182, a synthetic ERRγ modulator, may have potential in treating disorders related to bone resorption. [BMB Reports 2021; 54(5): 266-271].

Recent work has suggested a microbial dysbiosis association between the lung and gut in respiratory diseases. Here, we demonstrated that gut microbiome modulation attenuated emphysema development. To modulate the gut microbiome, fecal microbiota transplantation (FMT) and diet modification were adopted in mice exposed to smoking and poly I:C for the emphysema model. We analyzed the severity of emphysema by the mean linear intercept (MLI) and apoptosis by the fluorescent TUNEL assay. Microbiome analysis was also performed in feces and fecal extracellular vesicles (EVs). The MLI was significantly increased with smoking exposure. FMT or a high-fiber diet (HFD) attenuated the increase. Weight loss, combined with smoking exposure, was not noted in mice with FMT. HFD significantly decreased macrophages and lymphocytes in bronchoalveolar lavage fluid. Furthermore, IL-6 and IFN-γ were decreased in the bronchoalveolar lavage fluid and serum. The TUNEL score was significantly lower in mice with FMT or HFD, suggesting decreased cell apoptosis. In the microbiome analysis, Bacteroidaceae and Lachnospiraceae, which are alleged to metabolize fiber into short-chain fatty acids (SCFAs), increased at the family level with FMT and HFD. FMT and HFD attenuated emphysema development via local and systemic inhibition of inflammation and changes in gut microbiota composition, which could provide a new paradigm in COPD treatment.

Oleoylethanolamide (OEA), a bioactive lipid in bone, is known as an endogenous ligand for G protein-coupled receptor 119 (GPR119). Here, we explored the effects of OEA on osteoclast differentiation, function, and survival. While OEA inhibits osteoclast resorptive function by disrupting actin cytoskeleton, it does not affect receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation. OEA attenuates osteoclast spreading, blocks actin ring formation, and eventually impairs bone resorption. Mechanistically, OEA inhibits Rac activation in response to macrophage colony-stimulating factor (M-CSF), but not RANKL. Furthermore, the OEA-mediated cytoskeletal disorganization is abrogated by GPR119 knockdown using small hairpin RNA (shRNA), indicating that GPR119 is pivotal for osteoclast cytoskeletal organization. In addition, OEA induces apoptosis in both control and GPR119 shRNAtransduced osteoclasts, suggesting that GPR119 is not required for osteoclast apoptosis. Collectively, our findings reveal that OEA has inhibitory effects on osteoclast function and survival of mature osteoclasts via GPR119-dependent and GPR119-independent pathways, respectively.

Background/purpose: Skin commensal bacteria have been described to help orchestrate skin homeostasis, signaling through innate immunity pathways. This study for the first time aimed at studying the relationship between skin commensals and melanocytes after UVB exposure., Methods: An in vitro UVB radiation model with normal human epidermal melanocytes (NHMs) and skin commensal bacteria supernatant from Staphylococcus epidermidis and Propionibacterium acnes was established. Melanocytes DNA damage, cyclobutane pyrimidine dimers (CPD), and cellular proliferation marker Ki-67 were measured by ELISA and immunofluorescence staining. Cell apoptosis was assessed by flow cytometry and PCR array and RT-qPCR., Results: Normal human epidermal melanocytes are able to survive and proliferate while bearing DNA damage after UVB radiation. Skin commensal bacteria S. epidermidis and its by-product LTA promote melanocytes survival by inducing upregulation of TRAF1, CASP14, CASP5, and TP73. On the other hand, P. acnes can inhibit UVB-irradiated melanocytes survival by increasing apoptosis., Conclusion: Our studies show different aspects of commensal activity on melanocytes during irradiation. The possible balance achieved by the different skin commensal can influence NHM potential to become cancer cells., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

ABT-737, a BH3-mimetic small-molecule inhibitor, binds with very high affinity to Bcl-2, Bcl-xL and Bcl-w, and inhibits their activity. Aurora kinase is one of the serine/threonine kinase family members and is a vital and critical regulator of mitosis and meiosis. In the present study, we investigated the effects and mechanisms of a combined treatment of ABT-737 and VX-680 (Aurora kinase inhibitor) in human breast cancer MDA-MB‑435S cells. ABT-737 plus VX-680 induced caspase-dependent apoptosis in the human breast cancer cells. Combined treatment with ABT-737 and VX-680 led to the downregulation of Bcl-2 expression at the transcriptional level and the downregulation of c-FLIP and Mcl-1 expression at the post-transcriptional level. Overexpression of Bcl-2 or c-FLIP could not block the induction of apoptosis caused by the combined treatment with ABT-737 and VX-680. However, overexpression of Mcl-1 partially inhibited the induction of apoptosis. In contrast, the combined treatment with ABT-737 and VX680 had no effect on the apoptosis in normal cells. Taken together, our study demonstrated that combined treatment with ABT-737 and VX-680 induced apoptosis in anti‑apoptotic protein (Bcl-2 or c-FLIP)-overexpressing cells.

Despite conflicting results, there is evidence to suggest an inverse link between total body cholesterol levels and the risk of certain malignancies. Based on previous reports, this phenomenon appears to vary with cancer site, and, in particular, more consistent data on inverse relations was reported in the risk of gastric cancer. In the current study, the effect of cholesterol on gastric cancer cell viability was examined using an in vitro cell culture system. Addition of cholesterol in culture medium resulted in reduced viability and clonogenicity of SNU601, SNU638 and SNU216 gastric cancer cells by induction of both autophagic and apoptotic death. Transient inactivation of ERK1/2 was linked to reduction of cholesterol-mediated cell viability, and tumor necrosis factor‑related apoptosis-inducing ligand receptor 2 (TRAIL‑R2/DR5) was also involved in cell death signaling. In conclusion, these results imply that cholesterol can act as a signal regulator to modulate cell viability and that proper cellular cholesterol levels may be advantageous to suppress growth of gastric carcinomas.

This study was conducted to analyze a comprehensive panel of single nucleotide polymorphisms (SNPs) in genes in DNA repair and apoptosis pathways and determine the relationship between polymorphisms and treatment outcomes of patients with non-small cell lung cancer (NSCLC) treated with first-line paclitaxel-cisplatin chemotherapy. Three hundred eighty two patients with NSCLC were enrolled. Seventy-four SNPs in 48 genes (42 SNPs in 27 DNA repair pathway genes and 32 SNPs in 21 apoptotic pathway genes) were genotyped and their associations with chemotherapy response and overall survival (OS) were analyzed. Among SNPs in DNA repair genes, BRCA1 rs799917 was significantly associated with both chemotherapy response and OS. XRCC1 rs25487 exhibited a significant association with chemotherapy response and ERCC2 rs1052555 with OS. Four SNPs in apoptotic genes (TNFRSF1B rs1061624, BCL2 rs2279115, BIRC5 rs9904341, and CASP8 rs3769818) were significantly associated with OS, but not with response to chemotherapy. When the six SNPs which were associated with OS in individual analysis were combined, OS decreased as the number of bad genotypes increased (P(trend) = 2 × 10(-6)). Patients with 3, and 4-6 bad genotypes had significantly worse OS compared with those carrying 0-2 bad genotypes (adjusted hazard ratio [aHR] = 1.54, 95% CI = 1.14-2.08, P = 0.005; aHR = 2.10, 95% CI = 1.55-2.85, P = 2 × 10(-6), respectively). In conclusion, these findings suggest that the six SNPs identified, particularly their combined genotypes, could be used as biomarkers predicting chemotherapy response and survival of NSCLC patients treated with first-line paclitaxel-cisplatin chemotherapy., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Objective: The objective of this study was to evaluate the effects of silver nanoparticles (AgNPs) on the Toll-like receptor 2 (TLR-2) pathway in cultured cells., Study Design: Human chondrocytes, periodontal ligament (PDL) cells, and SCC-9 cells (squamous cell carcinoma from the tongue) were cultured and subjected to cytotoxicity assays. To evaluate the effects of AgNPs on the TLR-2 pathway, TLR-2 small interfering (si) RNA or TLR-2 antibodies were applied to the chondrocytes, followed by the application of AgNPs., Results: AgNPs induced dose-dependent effects on the examined cell types in terms of both cytotoxicity and TLR-2 expression levels. AgNP-mediated apoptosis was reduced after treatment with TLR-2 siRNA in both PDL cells and chondrocytes. Furthermore, functional blocking of TLR-2 with anti-TLR2 antibodies inhibited AgNP-mediated cytotoxicity. AgNPs increased c-Jun phosphorylation, an effect that was reversed after treatment with TLR-2 siRNA., Conclusions: The results indicate that AgNP-mediated apoptosis most likely occurs via the TLR-2 pathway., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Apoptosis plays an essential role in the elimination of mutated or transformed cells from the body. Therefore, polymorphisms of apoptosis-related genes may lead to an alteration in apoptotic capacity, thereby affecting the occurrence of TP53 mutations in lung cancer. We investigated the relationship between potentially functional polymorphisms of apoptosis-related genes and TP53 mutations in non-small cell lung cancer (NSCLC). Twenty-seven single nucleotide polymorphisms in 20 apoptosis-related genes were genotyped by a sequenome mass spectrometry-based genotyping assay in 173 NSCLCs and the associations with TP53 mutations in the entire coding exons (exons 2-11), including splicing sites of the gene, were analyzed. None of the 27 polymorphisms was significantly associated with the occurrence of TP53 mutations. This suggests that apoptosis-related genes may not play an important role in the occurrence of TP53 mutations in lung cancer.

Ursodeoxycholic acid (UDCA) is known as a suppressor of cholestatic liver diseases and colorectal cancer development. Here, we demonstrate that UDCA induces apoptosis without necrotic features in SNU601, SNU638, SNU1 and SNU216 human gastric cancer cells, implying its possible use as an effective chemotherapeutic agent in treatment of gastric cancer. UDCA-induced apoptosis was dominantly mediated by an extrinsic pathway dependent on caspase-8, -6 and -3. UDCA increased expression of death receptor 5 [(DR5), also known as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 2], and this DR appeared to be responsible for UDCA-induced apoptosis, as evidenced by DR5 knockdown. UDCA triggered formation of lipid rafts that played crucial roles in UDCA-induced apoptotic actions. Lipid rafts were required not only for provision of a proper site for DR5 action but also for mediation of DR5 expression. In addition, reactive oxygen species (ROS) and protein kinase C (PKC) δ appeared to be implicated in UDCA-induced raft-dependent DR5 expression. Our results indicate that UDCA-induced apoptosis is mediated by DR5 expression, which is regulated by the raft formation/ROS production/PKCδ activation pathway and DR5 localization into lipid rafts in gastric cancer cells. Tumor-suppressive activity of UDCA was confirmed in an in vivo system: UDCA (120 mg/kg/day) significantly decreased tumor growth in gastric cancer xenograft mice. Taken together, our results demonstrate that UDCA can be used as a potent chemotherapeutic agent for treatment of gastric cancer.

Hepatocellular carcinoma (HCC) is resistant to chemotherapy. Recently, however, several oxaliplatin-based combinatorial treatments have shown a promising anti-tumor activity in patients with HCC. Presently, we demonstrate that oxaliplatin triggers necrosis more than apoptosis in HepG2, SK-Hep1, SNU-423 and Hep3B HCC cells, while mainly inducing apoptosis in HCT116 and HT29 colon cancer cells. Interestingly, ursodeoxycholic acid (UDCA), a less hydrophobic bile acid that can suppress carcinogenesis, shifted oxaliplatin-induced necrosis to apoptosis in HepG2 cells. The same effect was produced by hydrophilic bile acids (tauroursodeoxycholic acid and taurohyodeoxycholic acid), but not by highly hydrophobic bile acids (deoxycholic acid and chenodeoxycholic acid). UDCA also triggered the necrosis-to-apoptosis switch when cotreated with other platinum-based chemotherapeutic drugs including cisplatin and carboplatin, suggesting that the cell death mode switching effect of UDCA is a general phenomenon when combined with platinum drugs. Oxaliplatin produced high level of reactive oxygen species (ROS) in HepG2 cells and UDCA significantly reduced oxaliplatin-induced ROS generation. In addition, N-acetyl-L-cysteine and the superoxide scavengers butylated hydroxyanisole and dihydroxybenzene-3,5-disulfonic acid attenuated necrosis, indicating a critical role(s) of ROS in occurrence of necrotic death. Apoptosis induced by combined treatment appeared to be mediated by p53-caspase 8-caspase 3 pathway. In conclusion, UDCA switches oxaliplatin-induced necrosis to apoptosis via inhibition of ROS production and activation of the p53-caspase 8 pathway in HepG2 cells. As necrosis and subsequent inflammation are implicated in tumor progression and malignancy, our results imply a potential improved efficacy of UDCA-combined chemotherapy in HCC by reducing inflammatory responses that may be triggered by oxaliplatin.

Previously, we showed that mild heat shock modulates patterns of cell death in response to glucose deprivation (GD), a common characteristic of the tumor microenvironment, by switching necrosis to apoptosis through ERK-dependent suppression of reactive oxygen species production in A549 cells. In the present study, we further examined the molecular mechanism underlying mild heat shock-induced necrosis-to-apoptosis switch. We examined the possible implication of p53 and heat shock proteins (HSPs) in the mechanism. Inhibition of p53 by pifithrin-alpha or p53 siRNA markedly suppressed apoptosis induced by heat shock/GD. On the other hand, silencing of HSP27, but not of HSP70, reversed heat shock/GD-induced apoptosis to necrosis, and HSP27 overexpression suppressed GD-induced necrosis. We further demonstrate that mild heat shock activated AKT and ERK1/2 through phosphorylation. Prevention of PI3K by LY294002 blocked heat shock/GD-induced apoptosis without reversing the cell death mode to necrosis, while inhibition of MEK1/2 by U0126 reversed heat shock/GD-induced apoptosis to necrosis, indicating a different role(s) of PI3K and ERK1/2 in heat shock/GD-induced cell death mode determination. We also found that mild heat shock increased HSP27 and p53 protein levels dependent on PI3K and suppressed the GD-induced increase in RIPA-insoluble HSP27 and p53 protein levels dependent on PI3K and ERK1/2. In conclusion, these results indicate that PI3K-dependent HSP27 and p53 induction and PI3K- and ERK1/2-dependent inhibition of the GD-induced increase in RIPA-insoluble HSP27 and p53 protein levels by heat play a key role(s) in heat shock-mediated switch of GD-induced necrosis to apoptosis.

Both cellular and clinical studies have shown that hyperthermia is one of the most potent sensitizers for the action of ionizing radiation. Although hyperthermic improvement in clinical outcome is suggested to be linked to its ability to induce cell cycle arrest and apoptosis, and to activate the immune system and to cause increases in blood flow and tumor oxygenation, the mechanism behind this is still unclear. Previously, we demonstrated that glucose deprivation (GD), a common characteristic of the tumor microenvironment, induced necrosis, which is implicated in tumor progression and aggressiveness, through the production of reactive oxygen species (ROS) in A549 lung carcinoma cells. We examined the effects of heat shock on ROS production and necrosis in response to GD. Here we show that mild, but not harsh, heat shock prevented GD-induced necrosis and switched the cell death mode to apoptosis in A549 cells through the ERK1/2 pathway that could suppress GD-induced CuZnSOD release and ROS production. These results demonstrate that contrary to severe heat shock, mild heat shock has the ability to decrease oxidative stress in cells, thereby causing the cell death mode switch from tumor promoting necrosis to tumor suppressive apoptosis, which may contribute to its anti-neoplastic activities.

Ethyl pyruvate (EP), a stable lipophilic pyruvate derivative, has been shown to exert anti-inflammatory activities through inhibiting the expression of various pro-inflammatory mediators as well as circulating levels of high mobility group box protein 1 (HMGB1) in a variety of in vitro and in vivo model systems. Necrotic cell death triggers an inflammatory response through release of HMGB1 in the extracellular space due to the membrane rupture. In an effort to better understand the pharmacological action mechanism that could explain the anti-inflammatory properties of EP, we examined the effects of EP on necrotic cell death in A549 lung adenocarcinoma cells in response to glucose deprivation (GD), a common characteristic of the tumor microenvironment. Here we show that EP prevented GD-induced necrosis and HMGB1 release and switched the cell death mode to apoptosis through inhibiting GD-induced CuZn superoxide dismutase release and ROS production. These results suggest that the necrosis-to-apoptosis switch activity of EP may contribute to its anti-inflammatory action and that EP may suppress tumor development possibly through its activity to induce the cell death mode switch from tumor promoting necrotic cell death to tumor suppressive apoptotic cell death.

The protective effects of betulin (BT) against cadmium (Cd)-induced cytotoxicity have been previously reported. However, the mechanisms responsible for these protective effects are unclear. Therefore, this study investigated the mechanisms responsible for the protection of BT against Cd-induced cytotoxicity in human hepatoma cell lines. The protection of BT against Cd cytotoxicity was more effective in the HepG2 than in the Hep3B cells. The protection of BT on Cd-induced cytotoxicity in the HepG2 cells appeared to be related to the inhibition of apoptosis, as determined by PI staining and DNA fragmentation analysis. The anti-apoptosis exerted by BT involved the blocking of Cd-induced reactive oxygen species (ROS) generation, the abrogation of the Cd-induced Fas upregulation, the blocking of caspase-8-dependent Bid activation, and subsequent inhibition of mitochondrial pathway. The BT pretreatment did not affect the p21 and p53 expression levels, when compared with those of the treated cells with Cd alone. BT induced the transient S phase arrest at an early stage and the G0/G1 arrest at a relatively late stage, but it did not observe the sub-G1 apoptotic peak. In the Hep3B cells, Cd did not induce ROS generation. The BT pretreatment partially inhibited the Cd-induced apoptosis, which was related with the incomplete blockage in caspase-9 or -3 activation, as well as in Bax activation. Taken together, it was found that Cd can induce apoptosis via the Fas-dependent and -independent apoptosis pathways. However, the observed protective effects of BT were clearly more sensitive to Fas-expressing HepG2 cells than to Fas-deficient Hep3B cells.

Leptin, the Ob gene product, has emerged recently as a key regulator of bone mass. However, the mechanism mediating leptin effect remains controversial. Because the action of leptin is dependent on its receptors, we analyzed their expression in osteoblast-lineage primary human bone marrow stromal cells (hBMSC). Both the short and long forms of leptin receptors were detected in hBMSC. Leptin significantly decreased the viability of hBMSC. This cytotoxic effect was prevented by Z-Val-Ala-Asp-fluoromethylketone, a pan-caspase inhibitor, implicating that leptin-induced hBMSC death was caspase-dependent. Further investigation demonstrated that leptin activated caspase-3 and caspase-9, but not caspase-8, and increased the cleavage of poly-(ADP-ribose) polymerase and cytochrome c release into cytosol. Leptin activated ERK, but not p38 and JNK, and up-regulated cPLA2 activity; the latter was abolished by pre-treatment of cells with the MEK inhibitor (PD98059 or U0126) or cPLA2 inhibitor (AACOCF3). PD98059, U0126, and AACOCF3 also diminished the leptin-induced cytochrome c release into cytosol, cell death, and caspase-3 activation. These data indicated that leptin induced hBMSC apoptosis via ERK/cPLA2/cytochrome c pathway with activation of caspase-9 and caspase-3, and cleavage of poly(ADP-ribose) polymerase. To our knowledge, this is the first study demonstrating the direct detrimental effect of leptin on bone cells.

Beta ig-h3 is a transforming growth factor-beta (TGF-beta)-induced cell-adhesive molecule and has an RGD sequence at its C-terminus. A previous report suggested that beta ig-h3 normally undergoes carboxy-terminal processing that results in the loss of the RGD sequence. RGD peptides appear to play various roles in cell function. Here we show that the RGD peptides released from beta ig-h3 may facilitate TGF-beta-induced apoptosis. We found that carboxy-terminal cleavage of beta ig-h3 occurred after its secretion, and that overexpression of the wild-type beta ig-h3 induced apoptosis, unlike the C-terminal deleted but RGD-containing mutant beta ig-h3, which is resistant to C-terminal processing. The beta ig-h3-induced apoptosis was abolished by either deletion of the RGD sequence or mutation of RGD to RAE. Synthetic peptides of ERGDEL and GRGDSP derived from beta ig-h3 and fibronectin, respectively, also induced apoptosis, unlike ERGEEL and GRGESP. Culture supernatants of cells overexpressing beta ig-h3 filtered to isolate molecules smaller than 3 kDa also induced apoptosis. A fusion protein composed of the N-terminal 100 amino acids of fibronectin and the RGD-containing C-terminal part of beta ig-h3 was also subjected to C-terminal cleavage and overexpression resulted in apoptosis. The anti-beta ig-h3 antibody blocks TGF-beta-induced apoptosis. Thus, beta ig-h3 may be important in regulating cell apoptosis by providing soluble RGD peptides.

It is known that many diabetic patients experience testicular atrophy. This study sought to investigate the effect of 4-hexylresorcinol (4HR) on testicular function in rats with streptozotocin (STZ)-induced diabetes, focusing on testicular weight, sperm motility, histological alterations, and serum testosterone levels to understand the efficacy of 4HR on testes. Our findings reveal that 4HR treatment significantly improves testicular health in diabetic rats. Notably, the STZ group exhibited a testicular weight of 1.22 ± 0.48 g, whereas the STZ/4HR group showed a significantly enhanced weight of 1.91 ± 0.26 g (p < 0.001), aligning closely with the control group's weight of 1.99 ± 0.17 g and the 4HR group's weight of 2.05 ± 0.24 g, indicating no significant difference between control and 4HR groups (p > 0.05). Furthermore, the STZ/4HR group demonstrated significantly improved sperm motility compared to the STZ group, with apoptotic indicators notably reduced in the STZ/4HR group relative to the STZ group (p < 0.05). These results underscore the therapeutic potential of 4HR for maintaining testicular function under diabetic conditions. [ABSTRACT FROM AUTHOR]

Aims Dual Ig domain-containing adhesion molecule (DICAM), a protein with homology to the junctional adhesion molecule family, has been demonstrated to interact with integrin αVβ3 that plays a critical role in angiogenesis. Here, we determined the role of DICAM during angiogenesis and the molecular mechanisms involved in the inhibition of angiogenesis. Methods and results DICAM was expressed on the endothelial cells of large vessels to small capillaries. In human umbilical vein endothelial cells (HUVECs), DICAM was up-regulated by vascular endothelial growth factor (VEGF) through the MEK/ERK and PI3K/AKT pathways. Furthermore, the exogenous expression of DICAM in HUVECs suppressed angiogenesis in vitro Matrigel and in vivo plug assays, and conversely, DICAM knockdown enhanced angiogenesis. In addition, DICAM inhibited HUVEC migration and accelerated apoptosis via down-regulation of Bcl-2, but did not affect viability or proliferation of HUVEC. Mechanistically, the exogenous expression of DICAM suppressed VEGF-induced phosphorylarion of AKT and p38 MAP kinase. When integrin signalling was activated by vitronectin, a forced expression of DICAM attenuated integrin β3/FAK signalling and downstream AKT and p38 MAP kinase signalling in HUVECs. Conclusion Collectively, DICAM suppressed angiogenesis by attenuating AKT and p38 MAP kinase signalling, which suggests that DICAM may be a novel negative regulator of angiogenesis. [ABSTRACT FROM PUBLISHER]

?ig-h3 is a transforming growth factor-? (TGF-?)-induced cell-adhesive molecule and has an RGD sequence at its C-terminus. A previous report suggested that ?ig-h3 normally undergoes carboxy-terminal processing that results in the loss of the RGD sequence. RGD peptides appear to play various roles in cell function. Here we show that the RGD peptides released from ?ig-h3 may facilitate TGF-?-induced apoptosis. We found that carboxy-terminal cleavage of ?ig-h3 occurred after its secretion, and that overexpression of the wild-type ?ig-h3 induced apoptosis, unlike the C-terminal deleted but RGD-containing mutant ?ig-h3, which is resistant to C-terminal processing. The ?ig-h3-induced apoptosis was abolished by either deletion of the RGD sequence or mutation of RGD to RAE. Synthetic peptides of ERGDEL and GRGDSP derived from ?ig-h3 and fibronectin, respectively, also induced apoptosis, unlike ERGEEL and GRGESP. Culture supernatants of cells overexpressing ?ig-h3 filtered to isolate molecules smaller than 3 kDa also induced apoptosis. A fusion protein composed of the N-terminal 100 amino acids of fibronectin and the RGD-containing C-terminal part of ?ig-h3 was also subjected to C-terminal cleavage and overexpression resulted in apoptosis. The anti-?ig-h3 antibody blocks TGF-?-induced apoptosis. Thus, ?ig-h3 may be important in regulating cell apoptosis by providing soluble RGD peptides.Oncogene (2003) 22, 2045-2053. doi:10.1038/sj.onc.1206269 [ABSTRACT FROM AUTHOR]

Abstract: Osteoclasts are polykaryons that have the unique capacity to degrade bone. Modulation of osteoclast formation and function is a promising strategy for the treatment of bone-destructive diseases. Here, we report that obovatol, a natural compound isolated from Magnolia obovata, inhibits receptor activator of nuclear factor kappa B (NF-κB) ligand (RANKL)-induced osteoclast differentiation in vitro and inflammatory bone loss in vivo. We found that obovatol strongly inhibited osteoclast formation from bone marrow-derived macrophages in a dose-dependent manner without cytotoxicity. Obovatol significantly suppressed RANKL-induced activation of NF-κB, c-Jun-N-terminal kinase, and extracellular signal-regulated kinase signaling pathways. Obovatol also inhibited RANKL-induced expression of the genes c-Fos and nuclear factor of activated T cells c1, which are transcription factors important for osteoclastogenesis. In addition to osteoclast differentiation, obovatol blocked cytoskeletal organization and abrogated the bone resorbing activity of mature osteoclast. Obovatol also accelerated osteoclast apoptosis through the induction of caspase-3 activation. Consistent with its in vitro anti-resorptive effect, obovatol prevented bone loss induced by lipopolysaccharide in vivo. Together, our data suggest that obovatol may be a useful therapeutic agent for the treatment of pathological bone disorders characterized by excessive osteoclastic bone resorption. [Copyright &y& Elsevier]