Endoplasmic reticulum stress mediates environmental particle-induced inflammatory response in bronchial epithelium.

While the detailed mechanisms for how particulate matter (PM) causes adverse health effects in the lungs remain largely unknown, endoplasmic reticulum (ER) stress has been implicated in PM-induced lung injury. The present study was undertaken to examine how/if ER stress might regulate PM-induced inflammation, and to begin to define potential underlying molecular mechanisms. Here, ER stress hallmarks were examined in human bronchial epithelial (HBE) cells exposed to PM. To confirm roles of certain pathways, siRNA targeting ER stress genes and an ER stress inhibitor were employed. Expression of select inflammatory cytokines and related signaling pathway components by the cells were assessed as well. The results showed that PM exposure induced elevations in two ER stress hallmarks, i.e. GRP78 and IRE1α, in time-and/or dose-related manners in the HBE cells. Inhibition of ER stress by siRNA for GRP78 or IRE1α significantly alleviated the PM-induced effects. Further, ER stress appeared to regulate PM-induced inflammation - likely through downstream autophagy and NF-κB pathways - as implied by studies showing that inhibition of ER stress by siRNA of GRP78 or IRE1α caused significant amelioration of PM-induced autophagy and subsequent activation of NF-κB pathways. Moreover, the ER stress inhibitor 4-PBA were used to confirm the protective effects against PM-induced outcomes. Together, the results suggest ER stress plays a deleterious role in PM-induced airway inflammation, possibly through activation of autophagy and NF-κB signaling. Accordingly, protocols/treatments that could lead to inhibited ER stress could potentially be effective for treatment of PM-related airway disorders.

Necroptosis Mediates Cigarette Smoke-Induced Inflammatory Responses in Macrophages.

Introduction: Cigarette smoke (CS)-induced inflammation in macrophages is involved in the pathological process of chronic obstructive pulmonary disease (COPD). Necroptosis, which is a form of programmed necrosis, has a close relationship with robust inflammation, while its roles in COPD are unclear. Materials and Methods: Necroptosis markers were measured in mouse alveolar macrophages and cultured bone marrow-derived macrophages (BMDMs). Necroptosis inhibitors were used to block necroptosis in BMDMs, and inflammatory cytokines were detected. We further explored the related signaling pathways. Results: In this study, we demonstrated the way in which necroptosis, in addition to its upstream and downstream signals, regulates CS-induced inflammatory responses in macrophages. We observed that CS exposure caused a significant increase in the levels of necroptosis markers (receptor interacting kinases [RIPK] 1 and 3) in mouse alveolar macrophages and BMDMs. Pharmacological inhibition of RIPK1 or 3 caused a significant suppression in CS extract (CSE)-induced inflammatory cytokines, chemokine ligands (CXCL) 1 and 2, and interleukin (IL)-6 in BMDMs. CSE-induced necroptosis was regulated by mitochondrial reactive oxygen species (mitoROS), which also promoted inflammation in BMDMs. Furthermore, necroptosis regulated CSE-induced inflammatory responses in BMDMs, most likely through activation of the nuclear factor-κB pathway. Conclusion: Taken together, our results demonstrate that mitoROS-dependent necroptosis is essential for CS-induced inflammation in BMDMs and suggest that inhibition of necroptosis in macrophages may represent effective therapeutic approaches for COPD patients.

A novel anticancer agent, retigeric acid B, displays proliferation inhibition, S phase arrest and apoptosis activation in human prostate cancer cells.

Retigeric acid B (RB), a naturally occurring pentacyclic triterpenic acid, has been noted for its antifungal properties in vitro. Here, we observed that RB inhibited prostate cancer cell proliferation and induced cell death in a dose-dependent manner, but exerted very little inhibitory effect on noncancerous prostate epithelial cell viability. Treatment of androgen-independent PC-3 cells with RB caused a moderate increase in p21(Cip1), and enforced the cell cycle arrest in the S phase. A block of S phase was accompanied with decreases in cyclin B, and increases in cyclin E and cyclin A proteins and phosphorylated retinoblastoma protein (pRb), whereas the expression of cdk2 remained almost unchanged in PC-3 cells exposed to RB. Moreover, RB significantly inhibited DNA synthesis with a dose-dependent reduction in the incorporation of BrdU into DNA, and enhanced apoptosis of PC-3 cells with induction of a higher ratio of Bax/Bcl-2 proteins, and activation of caspase-3 which, in turn, promoted the cleavage of poly (ADP-ribose) polymerase (PARP). However, pretreatment with the pan-caspase inhibitor z-VAD-fmk only partially alleviated RB-triggered apoptosis in PC-3 cells, suggesting the involvement of both caspase-dependent and caspase-independent pathways. Additionally, treatment of androgen-sensitive LNCaP cells with RB led to a reduction in the expression of androgen receptor (AR), and subsequently decreased the transactivity of AR. These observations help to support the search for promising candidates to treat prostate cancer.

Cyclic bisbibenzyls induce growth arrest and apoptosis of human prostate cancer PC3 cells.

AIM: To investigate the cytotoxic effects of four cyclic bisbibenzyls, Riccardin C (Ric), Pakyonol (Pak), Marchantin M (Mar), and Plagiochin E (Pla) against chemoresistant prostate cancer PC3 cells. METHODS: Cell growth was assayed by MTT method, and apoptotic related protein Bcl-2 and Bax, poly(ADP-ribose) polymerase (PARP) were examined by Western blotting. Cell cycle and apoptosis of PC3 cells were evaluated with flow cytometry and morphologic examinations. RESULTS: The four compounds inhibited proliferation and elicited cell death in a dose- and time-dependent manner with IC(50) values of 3.22 micromol/L for Ric, 7.98 micromol/L for Pak, 5.45 micromol/L for Mar, and 5.99 micromol/L for Pla, respectively. Furthermore, exposed to these chemicals caused a decrease in the antiapoptotic protein Bcl-2 and an increase in proapoptotic Bax expression. PARP cleavage and caspase-3 activity were also observed. CONCLUSION: The results suggest that cyclic bisbibenzyls could be used for the development of novel therapeutic chemicals against prostate cancer.

[The value of serum endostatin level in early diagnosis of lung cancer].

OBJECTIVE: To investigate value of serum endostatin level in early diagnosis of lung cancer. METHODS: ELISA was used to detect the level of serum endostatin at in 40 lung carcinoma patients, 18 males and 4 females, aged 59.50 +/- 14.58. The serum endostatin levels of the lung cancer patients at different clinical stage and of different pathological types were analyzed. The change of serum endostatin level before and after chemotherapy was observed. Twenty patients with benign lung disease and 20 normal persons were used as controls. RESULTS: (1) The serum endostatin level of the lung cancer patients was 10.71 +/- 9.99) ng/ml, significantly higher than those of the patients with benign lung diseases and the normal persons (4.79 +/- 1.23 ng/ml and 4.51 +/- 1.14 ng/ml, respectively, both P < 0.01). (2) The serum endostatin level of the lung cancer patients at the stage I and II were 13.63 +/- 13.13 ng/ml and 12.35 +/- 5.79 ng/ml respectively, booth significantly higher than that of the patients at the stage III (6.29 +/- 1.64, P = 0.023 and P = 0.023). (3) There were no significant differences in the serum endostatin level among the lung cancer patients with different pathological types. (4) The serum endostatin level of the lung cancer patients after chemotherapy was 7.83 +/- 1.48 ng/ml, significantly higher than that before the chemotherapy (5.59 +/- 1.74, P = 0.04). CONCLUSION: (1) Rising in lung cancer at stages I and II, level of serum may probably be used as the a sign in early diagnosis of lung cancer. (2) After chemotherapy the level of endostatin has a trend of rising. The changes of serum endostatin level will be used as a sign in observation of treatment and prognosis.