Phase Ib/II study of nivolumab combined with palliative radiation therapy for bone metastasis in patients with HER2-negative metastatic breast cancer.

Radiation therapy (RT) can enhance the abscopal effect of immune checkpoint blockade. This phase I/II study investigated the efficacy and safety of nivolumab plus RT in HER2-negative metastatic breast cancer requiring palliative RT for bone metastases. Cohort A included luminal-like disease, and cohort B included both luminal-like and triple-negative disease refractory to standard systemic therapy. Patients received 8 Gy single fraction RT for bone metastasis on day 0. Nivolumab was administered on day 1 for each 14-day cycle. In cohort A, endocrine therapy was administered. The primary endpoint was the objective response rate (ORR) of the unirradiated lesions. Cohorts A and B consisted of 18 and 10 patients, respectively. The ORR was 11% (90% CI 4-29%) in cohort A and 0% in cohort B. Disease control rates were 39% (90% CI 23-58%) and 0%. Median progression-free survival was 4.1 months (95% CI 2.1-6.1 months) and 2.0 months (95% CI 1.2-3.7 months). One patient in cohort B experienced a grade 3 adverse event. Palliative RT combined with nivolumab was safe and showed modest anti-tumor activity in cohort A. Further investigations to enhance the anti-tumor effect of endocrine therapy combined with RT plus immune checkpoint blockade are warranted.Trial registration number and date of registration UMIN: UMIN000026046, February 8, 2017; ClinicalTrials.gov: NCT03430479, February 13, 2018; Date of the first registration: June 22, 2017.

Everolimus pharmacokinetics and exposure-response relationship in Japanese patients with advanced breast cancer.

Background: Everolimus is one of the key drugs for the treatment of advanced breast cancer. The optimal target concentration range for everolimus therapy in patients with breast cancer has not yet been established. This study aimed to characterize everolimus pharmacokinetics (PK) and determine the relationship between blood concentration and efficacy as well as adverse events in patients with breast cancer. Methods: This was a prospective, observational PK study. Patients receiving everolimus between November 2015 and November 2018 at our hospital were enrolled in this study. The whole blood samples for the everolimus assay were collected at least two weeks after initiation of treatment or the last everolimus dose change. PK parameters were estimated using Bayesian analysis. Statistical differences in everolimus trough concentrations between patient cohorts were assessed using the Mann-Whitney test. Progression-free survival was assessed using the Kaplan-Meier method and the log-rank test. Results: Eighteen patients were enrolled in the study. The median follow-up period was 35 months. The most frequently observed adverse event was stomatitis (all grade 94%). There was high inter-individual variation in PK parameters such as clearance [range: 5.1-21.3 L/h/70 kg and co-efficient of variation (CV): 38.5%] and volume of distribution of the central compartment (range: 9.9-103.6 L/70 kg and CV: 57.8%). The trough concentrations at dose-limiting toxicities were significantly higher than trough concentrations in the absence of these toxicities (p = 0.0058). Progression-free survival was significantly longer in the 10-20 ng/ml group than in the other groups (p = 0.0078). Conclusion: This study characterized the everolimus PK parameters in Japanese patients with breast cancer. High everolimus exposure was found to be associated with poor tolerability. Based on our data, trough concentrations in the range of 10-20 ng/ml may be associated with prolonged progression-free survival. Thus, determining the blood concentration of everolimus and subsequent dose adjustments will potentially reduce side effects and enhance the therapeutic effect in Japanese patients with advanced breast cancer.

Optimization of prediction methods for risk assessment of pathogenic germline variants in the Japanese population.

Predicting pathogenic germline variants (PGVs) in breast cancer patients is important for selecting optimal therapeutics and implementing risk reduction strategies. However, PGV risk factors and the performance of prediction methods in the Japanese population remain unclear. We investigated clinicopathological risk factors using the Tyrer-Cuzick (TC) breast cancer risk evaluation tool to predict BRCA PGVs in unselected Japanese breast cancer patients (n = 1,995). Eleven breast cancer susceptibility genes were analyzed using target-capture sequencing in a previous study; the PGV prevalence in BRCA1, BRCA2, and PALB2 was 0.75%, 3.1%, and 0.45%, respectively. Significant associations were found between the presence of BRCA PGVs and early disease onset, number of familial cancer cases (up to third-degree relatives), triple-negative breast cancer patients under the age of 60, and ovarian cancer history (all P < .0001). In total, 816 patients (40.9%) satisfied the National Comprehensive Cancer Network (NCCN) guidelines for recommending multigene testing. The sensitivity and specificity of the NCCN criteria for discriminating PGV carriers from noncarriers were 71.3% and 60.7%, respectively. The TC model showed good discrimination for predicting BRCA PGVs (area under the curve, 0.75; 95% confidence interval, 0.69-0.81). Furthermore, use of the TC model with an optimized cutoff of TC score ≥0.16% in addition to the NCCN guidelines improved the predictive efficiency for high-risk groups (sensitivity, 77.2%; specificity, 54.8%; about 11 genes). Given the influence of ethnic differences on prediction, we consider that further studies are warranted to elucidate the role of environmental and genetic factors for realizing precise prediction.

Genetic and clinical landscape of breast cancers with germline BRCA1/2 variants.

The genetic and clinical characteristics of breast tumors with germline variants, including their association with biallelic inactivation through loss-of-heterozygosity (LOH) and second somatic mutations, remain elusive. We analyzed germline variants of 11 breast cancer susceptibility genes for 1,995 Japanese breast cancer patients, and identified 101 (5.1%) pathogenic variants, including 62 BRCA2 and 15 BRCA1 mutations. Genetic analysis of 64 BRCA1/2-mutated tumors including TCGA dataset tumors, revealed an association of biallelic inactivation with more extensive deletions, copy neutral LOH, gain with LOH and younger onset. Strikingly, TP53 and RB1 mutations were frequently observed in BRCA1- (94%) and BRCA2- (9.7%) mutated tumors with biallelic inactivation. Inactivation of TP53 and RB1 together with BRCA1 and BRCA2, respectively, involved LOH of chromosomes 17 and 13. Notably, BRCA1/2 tumors without biallelic inactivation were indistinguishable from those without germline variants. Our study highlights the heterogeneity and unique clonal selection pattern in breast cancers with germline variants.

ER-resident sensor PERK is essential for mitochondrial thermogenesis in brown adipose tissue.

Mitochondria play a central role in the function of brown adipocytes (BAs). Although mitochondrial biogenesis, which is indispensable for thermogenesis, is regulated by coordination between nuclear DNA transcription and mitochondrial DNA transcription, the molecular mechanisms of mitochondrial development during BA differentiation are largely unknown. Here, we show the importance of the ER-resident sensor PKR-like ER kinase (PERK) in the mitochondrial thermogenesis of brown adipose tissue. During BA differentiation, PERK is physiologically phosphorylated independently of the ER stress. This PERK phosphorylation induces transcriptional activation by GA-binding protein transcription factor α subunit (GABPα), which is required for mitochondrial inner membrane protein biogenesis, and this novel role of PERK is involved in maintaining the body temperatures of mice during cold exposure. Our findings demonstrate that mitochondrial development regulated by the PERK-GABPα axis is indispensable for thermogenesis in brown adipose tissue.

Effectiveness and safety of surgical glove compression therapy as a prophylactic method against nanoparticle albumin-bound-paclitaxel-induced peripheral neuropathy.

BACKGROUND: We have developed a surgical glove (SG)-compression therapy and reported that this method significantly reduced the overall occurrence of grade 2 or higher nanoparticle albumin-bound-paclitaxel (nab-PTX)-induced peripheral neuropathy (PN) from 76.1% to 21.4%. In this multicenter single-arm confirmatory study, we investigated the efficacy and safety of SG-compression therapy for the prevention of nab-PTX-induced PN, compared with the incidence of grade 2 or higher PN in published literature as controls. PATIENTS AND METHODS: Primary breast cancer patients who received 260 mg/m2 of nab-PTX were eligible for this study. Patients wore two SGs (one size smaller than the tight-fitting size) in each hand for 90 min. PN was evaluated at each treatment cycle using the Common Terminology Criteria for Adverse Events (CTCAE) version 4.0 and the Patient Neurotoxicity Questionnaire (PNQ). The temperature of each fingertip was measured using thermography. RESULTS: Between October 2016 and June 2017, 58 patients were evaluated. The incidence of CTCAE grade 2 or higher PN was as low as 13.8% following SG-compression therapy. A goodness-of-fit test proved that the overall incidence of 13.8% grade 2 or higher PN in this study was comparable to the hypothesis-predicted value (13%). No adverse events, including compression intolerance or skin disorders caused by use of SG, were observed. SG-compression therapy significantly reduced the temperature of each fingertip by 1.3°C-2.3 °C compared to pre-chemotherapy level. CONCLUSIONS: This study suggested the safety and efficacy of SG-compression therapy for the amelioration of CIPN. CLINICAL TRIAL NUMBER: UMIN 000024836.

Monitoring Lipid Droplet Dynamics in Living Cells by Using Fluorescent Probes.

We have developed three types of lipid droplet (LD)-specific fluorescent probes for live-cell imaging, Lipi-Blue, Lipi-Green, and Lipi-Red, which exhibit fluorescence upon being incorporated into LDs both of living and of fixed cells. These Lipi-probes are LD-specific probes that contain a pyrene or perylene group as a fluorescent scaffold and can be used to observe dynamics of LD in live cells and also interrelations with other organelles by simultaneous staining with multiple organelle-specific probes. Additionally, Lipi-Blue and Lipi-Green allow monitoring LDs in live cells even for 48 h after the staining. Here we show that newly formed LDs and previously existed LDs can be separately monitored in a single cell by using these probes and that intercellular transfer of whole LDs is observed in KB cells, but not in HepG2 cells under the same culturing condition. These findings indicate that newly developed LD-specific probes are useful to analyze the dynamics of LDs in live cells.

Evaluation of health-related quality of life via the Computer-Based Health Evaluation System (CHES) for Japanese metastatic breast cancer patients: a single-center pilot study.

BACKGROUND: The main purposes of metastatic breast cancer (MBC) treatment are to prolong survival and maintain health-related quality of life (HRQOL). Compliance with the HRQOL assessment can be poor, particularly among patients who receive long-term treatment. One possible solution to overcoming this problem is to engage in real-time home monitoring by having patients report outcomes on their personal electronic devices. The objective of this study was to investigate compliance with HRQOL monitoring from home among MBC patients using the Computer-Based Health Evaluation System (CHES) to collect patient data. METHODS: Sixteen MBC patients who received outpatient chemotherapy or endocrine therapy, both with and without targeted therapy, were recruited. One eligibility criterion was the availability of a personal electronic device with access to the Internet. Patients were asked to enter HRQOL ratings from their personal electronic devices via CHES once every week for 12 weeks. The European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ C30) was used to evaluate HRQOL. The outcome examined was the questionnaire collection rate. RESULTS: Six patients (37.5%) were treated with chemotherapy only, one (6.2%) with endocrine therapy only, three (18.8%) with a combination of chemotherapy and targeted therapy, and six (37.5%) with a combination of endocrine and targeted therapy. Median questionnaire collection rate for the total of 12 weeks was 84.6% (interquartile range 44.3-100). The reasons for missing data were worsening of disease, forgetting, and device malfunction. CONCLUSIONS: Compliance with electronic HRQOL data collection in this cohort was acceptable, considering the general ideal collection rate of 70-80%. We are conducting a prospective study to determine whether the use of CHES to input electronic real-time feedback of HRQOL ratings improves patients' overall HRQOL.

Japan Gastroenterological Endoscopy Society guidelines for endoscopic papillary large balloon dilation.

The Japan Gastroenterological Endoscopy Society has developed the 'EPLBD Clinical Practice Guidelines' as fundamental guidelines based on new scientific techniques. EPLBD is a treatment method that has recently become widely used for choledocolithiasis. The evidence level in this field is usually low, and in many instances, the recommendation grading has to be determined on the basis of expert consensus. At this point, the guidelines are divided into the following six sections according to the 'EST Clinical Practice Guidelines': (i) Indications, (ii) procedures, (iii) special cases, (iv) procedure-related adverse events, (v) treatment outcomes, and (vi) postoperative follow up observation.

Prevalence of hypothyroidism among patients with breast cancer treated with radiation to the supraclavicular field: a single-centre survey.

PURPOSE: We investigated the prevalence of hypothyroidism (HT) in patients with breast cancer who received radiation therapy to the supraclavicular (SC) field to evaluate the effect of radiation on thyroid. METHODS: Between April 2007 and May 2016, consecutive patients with invasive breast cancer who received SC radiation were recruited. Thyroid-stimulating hormone (TSH) and free thyroxine (fT4) were measured between April and August 2016. On the basis of the radiation-planning CT images, thyroid volume was calculated and dose-volume parameters were estimated. The endpoints were the prevalence of HT as determined by high levels of TSH and low levels of fT4 in serum, and the prevalence of subclinical HT, determined by high-serum TSH and normal fT4. RESULTS: Among the 68 consecutive patients, 26 were excluded from evaluation (10 patients died, 6 had a history of previous thyroid disease and 10 were lost to follow-up). One (2.4%) and six (14.3%) of these patients had HT and subclinical HT, respectively, with a mean TSH level of 8.27 µU/mL. By univariate analysis, a predictive factor of HT and subclinical HT was a thyroid volume <8 cm3 (OR 6.44, 95% CI 1.14 to 36.6; p=0.043). Multivariate analysis also showed an association between thyroid volume <8 cm3 and HT or subclinical HT (OR 18.48, 95% CI 1.48 to 230.86; p=0.024). CONCLUSIONS: The prevalence of HT in patients with breast cancer studied was relatively low. Although thyroid volume appeared to be a predictive marker of HT in this cohort, further prospective evaluation is needed.

Evaluation of the effect of compression therapy using surgical gloves on nanoparticle albumin-bound paclitaxel-induced peripheral neuropathy: a phase II multicenter study by the Kamigata Breast Cancer Study Group.

PURPOSE: To investigate the efficacy of using surgical glove (SG) compression therapy to prevent nanoparticle albumin-bound paclitaxel (nab-PTX)-induced peripheral neuropathy. PATIENTS AND METHODS: Patients with primary and recurrent breast cancer who received 260 mg/m2 of nab-PTX were eligible for this case-control study. Patients wore two SGs of the same size, i.e., one size smaller than the size that fit their dominant hand, for only 90 min. They did not wear two SGs on the non-dominant hand, which served as the control hand. Peripheral neuropathy was evaluated at each treatment cycle using common terminology criteria for adverse events (CTCAE) version 4.0 and the Patient Neurotoxicity Questionnaire. The temperature of each fingertip of the compression SG-protected hand and control hand was measured using thermography. RESULTS: Between August 2013 and January 2016, 43 patients were enrolled and 42 were evaluated. The occurrence rates of CTCAE grade 2 or higher sensory and motor peripheral neuropathies were significantly lower for SG-protected hands than for control hands (sensory neuropathy 21.4 vs. 76.1 %; motor neuropathy 26.2 vs. 57.1 %). No patients withdrew from this study because they could not tolerate the compression from the SGs. SG compression therapy significantly decreased the temperature of each fingertip by 1.6-2.2 °C as compared with the temperature before chemotherapy (p < 0.0001). CONCLUSIONS: SG compression therapy is effective for reducing nab-PTX-induced peripheral neuropathy. The nab-PTX exposure to the peripheral nerve may be decreased because the SG decreases microvascular flow to the fingertip.

Evaluation of the Clinical Utility of the ICG Fluorescence Method Compared with the Radioisotope Method for Sentinel Lymph Node Biopsy in Breast Cancer.

PURPOSE: This study compared the clinical utility of indocyanine green (ICG) fluorescence and radioisotope (RI) for sentinel lymph node (SLN) detection in breast cancer. METHODS: Women with node-negative breast cancer underwent SLN biopsy using ICG fluorescence and RI. The primary end point was the sensitivity of ICG fluorescence compared with RI in the patients with tumor-positive SLNs. Secondary end points included detection rates for SLN, the additive effect of ICG fluorescence to RI, signature of positive SLNs according to tier, and adverse events related to ICG administration. RESULTS: A total of 847 women with clinical node-negative breast cancer underwent SLN biopsy, and 821 patients were included in the per-protocol analysis. SLN mapping was performed using ICG fluorescence and RI. The overall detection of SLNs using ICG fluorescence was identical to RI (97.2 vs. 97.0 %, P = 0.88), and the combination of both methods achieved a significant improvement compared with RI alone (99.8 vs. 97.0 %, P < 0.001). The detection rate for tumor-positive SLN was 93.3 % for ICG fluorescence and 90.0 % for RI, and the sensitivity of the ICG fluorescence method was 95.7 % (95 % CI 91.3-98.3, P = 0.11). The additional use of ICG significantly improved positive SLN detection for RI (97.2 vs. 90.0 %, P < 0.001). There were no serious adverse events related to hypersensitivity to ICG. CONCLUSIONS: The ICG fluorescence method may be an acceptable alternative to SLN detection using RI in breast cancer.

Pre-emptive Quality Control Protects the ER from Protein Overload via the Proximity of ERAD Components and SRP.

Cells possess ER quality control systems to adapt to ER stress and maintain their function. ER-stress-induced pre-emptive quality control (ER pQC) selectively degrades ER proteins via translocational attenuation during ER stress. However, the molecular mechanism underlying this process remains unclear. Here, we find that most newly synthesized endogenous transthyretin proteins are rerouted to the cytosol without cleavage of the signal peptide, resulting in proteasomal degradation in hepatocytes during ER stress. Derlin family proteins (Derlins), which are ER-associated degradation components, reroute specific ER proteins, but not ER chaperones, from the translocon to the proteasome through interactions with the signal recognition particle (SRP). Moreover, the cytosolic chaperone Bag6 and the AAA-ATPase p97 contribute to the degradation of ER pQC substrates. These findings demonstrate that Derlins-mediated substrate-specific rerouting and Bag6- and p97-mediated effective degradation contribute to the maintenance of ER homeostasis without the need for translocation.

Stress responses from the endoplasmic reticulum in cancer.

The endoplasmic reticulum (ER) is a dynamic organelle that is essential for multiple cellular functions. During cellular stress conditions, including nutrient deprivation and dysregulation of protein synthesis, unfolded/misfolded proteins accumulate in the ER lumen, resulting in activation of the unfolded protein response (UPR). The UPR also contributes to the regulation of various intracellular signaling pathways such as calcium signaling and lipid signaling. More recently, the mitochondria-associated ER membrane (MAM), which is a site of close contact between the ER and mitochondria, has been shown to function as a platform for various intracellular stress responses including apoptotic signaling, inflammatory signaling, the autophagic response, and the UPR. Interestingly, in cancer, these signaling pathways from the ER are often dysregulated, contributing to cancer cell metabolism. Thus, the signaling pathway from the ER may be a novel therapeutic target for various cancers. In this review, we discuss recent research on the roles of stress responses from the ER, including the MAM.

Prevalence and risk factors of bone metastasis and skeletal related events in patients with primary breast cancer in Japan.

BACKGROUND: Bone metastasis (BM) is important for studying systemic spread of breast cancer. It often causes skeletal-related events (SREs) that worsen quality of life. We investigated the prevalence and risk factors for BM and SRE using a dataset from the Breast Oncology Research Network (BORN) in Japan. PATIENTS AND METHODS: We collected data on primary breast cancer patients with node-positive or node-negative disease at intermediate to high risk of recurrence. The risk factors affecting the BM-free rate, SRE-free rate and overall survival were analyzed by using the Cox proportional hazard model. RESULTS: Data of 1,779 patients who were diagnosed with breast cancer during 2003-2005 were collected from the BORN and 1,708 cases were used for analysis. The median follow-up duration was 5.71 years. BM developed in 193 cases (11.3 %) and the BM-free rate at 5 years was 89.2 %. The annual hazard ratio of BM development differs remarkably according to the tumor subtype. SREs occurred in 133 (68.9 %) out of 193 patients and the SRE-free rate at 5 years was 92.6 %. In the multivariate analysis, clinical stage (P < 0.0001), number of lymph node (LN) metastases (P = 0.0029), tumor subtype (P = 0.034) and progesterone receptor status (P = 0.038) were independently significant risk factors for BM-free rate, but only clinical stage (P < 0.0001) and number of LN metastases (P = 0.0004) significantly correlated with SRE-free rate. CONCLUSIONS: This retrospective study clarifies the prevalence and risk factors for BM and SRE in Japanese breast cancer patients. Our results show the importance of considering subtype in the care of BM and SRE.

Selective, potent blockade of the IRE1 and ATF6 pathways by 4-phenylbutyric acid analogues.

BACKGROUND AND PURPOSE: 4-Phenylbutyric acid (4-PBA) is a chemical chaperone that eliminates the accumulation of unfolded proteins in the endoplasmic reticulum (ER). However, its chaperoning ability is often weak and unable to attenuate the unfolded protein response (UPR) in vitro or in vivo. To develop more potent chemical chaperones, we synthesized six analogues of 4-PBA and evaluated their pharmacological actions on the UPR. EXPERIMENTAL APPROACH: NRK-52E cells were treated with ER stress inducers (tunicamycin or thapsigargin) in the presence of each of the 4-PBA analogues; the suppressive effects of these analogues on the UPR were assessed using selective indicators for individual UPR pathways. KEY RESULTS: 2-POAA-OMe, 2-POAA-NO2 and 2-NOAA, but not others, suppressed the induction of ER stress markers GRP78 and CHOP. This suppressive effect was more potent than that of 4-PBA. Of the three major UPR branches, the IRE1 and ATF6 pathways were markedly blocked by these compounds, as indicated by suppression of XBP1 splicing, inhibition of UPRE and ERSE activation, and inhibition of JNK phosphorylation. Unexpectedly, however, these agents did not inhibit phosphorylation of PERK and eIF2α triggered by ER stress. These compounds dose-dependently inhibited the early activation of NF-κB in ER stress-exposed cells. 2-POAA-OMe and 2-POAA-NO2 also inhibited ER stress-induced phosphorylation of Akt. CONCLUSION AND IMPLICATIONS: The 4-PBA analogues 2-POAA-OMe, 2-POAA-NO2 and 2-NOAA strongly inhibited activation of the IRE1 and ATF6 pathways and downstream pathogenic targets, including NF-κB and Akt, in ER stress-exposed cells. These compounds may be useful for therapeutic intervention in ER stress-related pathological conditions.

Dual regulation of cadmium-induced apoptosis by mTORC1 through selective induction of IRE1 branches in unfolded protein response.

Cadmium (Cd) causes generation of reactive oxygen species (ROS) that trigger renal tubular injury. We found that rapamycin, an inhibitor of mTORC1, attenuated Cd-induced apoptosis in renal tubular cells. Knockdown of Raptor, a positive regulator of mTORC1, also had the similar effect. However, rapamycin did not alter generation of ROS, suggesting that mTORC1 is a target downstream of ROS. Indeed, ROS caused activation of mTORC1, which contributed to induction of a selective branch of the unfolded protein response (UPR); i.e., the IRE1 pathway. Although Cd triggered three major UPR pathways, activation of mTORC1 by Cd did not contribute to induction of the PERK-eIF2α and ATF6 pathways. Consistently, knockdown of Raptor caused suppression of JNK without affecting the PERK-eIF2α pathway in Cd-exposed cells. Knockdown of TSC2, a negative regulator of mTORC1, caused activation of mTORC1 and enhanced Cd induction of the IRE1-JNK pathway and apoptosis without affecting other UPR branches. Inhibition of IRE1α kinase led to suppression of JNK activity and apoptosis in Cd-treated cells. Dominant-negative inhibition of JNK also suppressed Cd-induced apoptosis. In contrast, inhibition of IRE1α endoribonuclease activity or downstream XBP1 modestly enhanced Cd-induced apoptosis. In vivo, administration with rapamycin suppressed activation of mTORC1 and JNK, but not eIF2α, in the kidney of Cd-treated mice. It was correlated with attenuation of tubular injury and apoptotic cell death in the tubules. These results elucidate dual regulation of Cd-induced renal injury by mTORC1 through selective induction of IRE1 signaling.

Pleiotropic potential of dehydroxymethylepoxyquinomicin for NF-κB suppression via reactive oxygen species and unfolded protein response.

Dehydroxymethylepoxyquinomicin (DHMEQ) is a low-m.w. compound that strongly inhibits NF-κB. Previous reports showed that DHMEQ directly binds to specific cysteine residues of NF-κB subunits and thereby inhibits their nuclear translocation and DNA binding. In this work, we describe novel mechanisms by which DHMEQ suppresses cytokine-triggered activation of NF-κB. We found that sustained exposure of renal tubular cells to DHMEQ blocked TNF-α- and IL-1ß-induced TGF-ß-activated kinase 1 (TAK1) phosphorylation, a crucial event for NF-κB activation upstream of IκB kinase. This inhibition was mediated by reactive oxygen species (ROS), because of the following: 1) DHMEQ caused generation of ROS; 2) pretreatment with ROS generator inhibited cytokine-induced TAK1 phosphorylation and NF-κB activation; and 3) scavenging of ROS attenuated the suppressive effects of DHMEQ on TAK1 and NF-κB. We also found that DHMEQ caused the unfolded protein response (UPR) through generation of ROS. Alleviation of the UPR by chemical and genetic chaperones partially attenuated the suppressive effect of DHMEQ on NF-κB. The UPR-mediated inhibition of NF-κB occurred downstream of degradation of IκBα and phosphorylation of p65. Subsequent experiments revealed the following: 1) DHMEQ caused selective induction of C/EBPß through the UPR; 2) overexpression of C/EBPß suppressed activation of NF-κB; 3) knockdown of C/EBPß attenuated the inhibitory effect of DHMEQ; and 4) DHMEQ-induced expression of C/EBPß did not affect TNF-α-triggered degradation of IκBα and phosphorylation of p65. These results suggest that, in addition to its known effect on nuclear translocation of NF-κB, DHMEQ interferes with the cytokine-induced NF-κB signaling via generation of ROS at both upstream and downstream of the IκB kinase-IκB level.

Blockade of Smad signaling by 3'-deoxyadenosine: a mechanism for its anti-fibrotic potential.

Cordyceps militaris has been used in Eastern countries for the treatment of various diseases including chronic kidney diseases. However, there are no reports that identified its active entities and molecular mechanisms underlying its therapeutic effectiveness. 3'-Deoxyadenosine is a major nucleoside derivative isolated from C. militaris. Some reports suggested that both C. militaris and 3'-deoxyadenosine have anti-inflammatory and anti-fibrotic effects. In the present report, we investigated whether and how 3'-deoxyadenosine interferes with fibrogenic processes in the kidney. For this purpose, we examined effects of 3'-deoxyadenosine on the expression of collagens triggered by transforming growth factor-ß (TGF-ß1) and bone morphogenetic protein-4 (BMP-4), especially focusing on the regulation of Smad signaling in vitro and in vivo. We found that 3'-deoxyadenosine suppressed expression of collagens induced by TGF-ß1 and BMP-4 dose dependently. This suppression occurred at the transcriptional level and was correlated with blunted activation of the CAGA box and the BMP-responsive element. The suppressive effect on the TGF-ß/BMP signaling was mediated mainly by adenosine transporter and partially by the A3 adenosine receptor, but not A1/A2 adenosine receptors. 3'-Deoxyadenosine reduced levels of both phosphorylated and total Smad proteins (Smad1, 2 and 3) dose dependently. It was mainly ascribed to transcriptional suppression, but not to enhanced protein degradation and eIF2α-mediated translational suppression. Consistent with the in vitro results, in vivo administration with 3'-deoxyadenosine reduced the levels of phosphorylated and total Smad proteins, as well as the levels of Smad mRNAs, in the kidney subjected to unilateral ureteral obstruction. It was associated with blunted induction of type I collagen and α-smooth muscle actin, a decrease in the number of interstitial myofibroblasts and reduced fibrotic area. These results suggest that 3'-deoxyadenosine interferes with the TGF-ß and BMP signaling via downregulation of Smads, which may underlie the anti-fibrotic effect of this agent. 3'-Deoxyadenosine may be useful for therapeutic intervention in various TGF-ß-related fibrotic disorders.

Unfolded protein response causes a phenotypic shift of inflamed glomerular cells toward redifferentiation through dual blockade of Akt and Smad signaling pathways.

During recovery from acute glomerulonephritis, cell proliferation, matrix expansion, and expression of the dedifferentiation marker α-smooth muscle actin (α-SMA) subside spontaneously. However, the molecular mechanisms underlying this recovery process remain elusive. In mesangioproliferative glomerulonephritis, the unfolded protein response (UPR) is induced in activated, dedifferentiated mesangial cells. We investigated the role of the UPR in mesangial cell deactivation and redifferentiation and found that, during experimental glomerulonephritis in rats, reinforcement of the UPR significantly attenuated mesangial cell proliferation, matrix expansion, and expression of α-SMA. Consistent with this in vivo result, induction of the UPR suppressed cell proliferation and transcriptional expression of type IV collagen (ColIV) and α-SMA in activated mesangial cells. The UPR reduced phosphorylation of Akt in vitro and in vivo, and it was responsible for attenuation of cell proliferation. The UPR also preferentially depressed levels of total and phosphorylated Smads without affecting transcriptional levels, and it was responsible for suppression of ColIV and α-SMA. Translational suppression via the eIF2α pathway, but not proteasome-mediated protein degradation, was responsible for the down-regulation of Smads. These results suggest the novel potential of the UPR to facilitate a phenotypic shift of activated glomerular cells toward deactivation and redifferentiation. The UPR may serve as endogenous machinery that supports recovery of glomeruli from acute inflammation.