Corticosterone exerts immunostimulatory effects on macrophages via endoplasmic reticulum stress

BACKGROUND

: Glucocorticoids are the central effector hormones for the hypothalamic-pituitary-adrenal axis. However, the effects of endogenous glucocorticoids on the immune system are not understood completely.

METHODS

: Macrophage function (adherence, chemotaxis and cytokine production) was assessed in the presence of increasing concentrations of corticosterone. The role of endoplasmic reticulum (ER) stress in corticosterone immunoregulation was determined with thapsigargin and plasmid pGCL-GFP-siXBP1. Mifepristone was used to determine the role of glucocorticoid receptor in the corticosterone-induced ER stress response.

RESULTS

: Corticosterone exerted immunostimulatory effects on macrophage function at low concentrations. No effects were observed at high concentrations in the absence of immunological stimulation. Low-dose corticosterone induced ER stress, which was correlated to the corticosterone immunostimulatory activities. Expression of X box-binding protein (XBP) 1, but not activating transcription factor 6, was significantly increased at both mRNA and protein levels only in the presence of low-dose corticosterone. Inhibition of XBP1 expression with small interfering RNA significantly inhibited the corticosterone immunostimulatory effects. In addition, pretreatment of macrophages with mifepristone significantly inhibited the expression of glucose response protein 78 and XBP1 in macrophages by low-dose corticosterone.

CONCLUSION

: At low concentrations, endogenous glucocorticoids exert immunostimulatory actions on macrophages. The underlying mechanisms may be correlated to ER stress via the glucocorticoid receptor, in which XBP1 plays an important role.

Multiple T cell epitope peptides suppress allergic responses in an egg allergy mouse model by the elicitation of forkhead box transcription factor 3- and transforming growth factor-beta-associated mechanisms

BACKGROUND

Peptide-based immunotherapy (PIT) represents an attractive approach for targeted interventions in immunological disorders, but has not been widely explored in the context of food allergy.

OBJECTIVE

In this study, we built on the information obtained from the recent identification of three immunodominant T cell epitopes of hen ovalbumin (OVA), a major egg allergen, to assess the therapeutic potential of PIT for food allergy, using the BALB/c mouse model.

METHODS

Groups of mice were sensitized to OVA by repeated oral gavages, and subsequently administered with single or multiple synthetic peptides containing OVA T cell epitopes. Following the peptide administration period, all mice were orally challenged with high doses of OVA to elicit active anaphylaxis. Serum, spleen, and intestinal tissues were collected for the determination of immunoglobulin levels, cytokine secretions, and intestinal gene expression.

RESULTS

Significantly lower anaphylactic scores were exhibited by mice that received multiple epitope-containing peptides, accompanied by lower serum histamine and OVA-specific IgE levels, compared with placebo-treated mice. Mechanistically, the quantification of cytokine secretions in splenocyte cultures revealed a T helper type 1-biased response (IFN-gamma) in all peptide-treated mice to the detriment of a T helper type 2-response (IL-4). Interestingly, a similar cytokine expression profile was determined in intestinal tissues, accompanied by a pronounced mRNA expression of regulatory molecules TGF-beta and forkhead box transcription factor 3 (FOXP3). These data suggest the activation of local repressive mechanisms mediated by subsets of regulatory T cells.

CONCLUSION

We demonstrated the therapeutic potential of PIT in a mouse model of food allergy model and provided evidence that mechanistic pathways entailing regulatory molecules TGF-beta and FOXP3, stand as promising trails for the further understanding of peptide-based strategies for food allergy.

Partial cancerous changes eventually developing into superficial spreading cancer over 18 months

In this report, we describe a patient presenting with the superficial spreading type of early gastric cancer (egc) accompanied by cancerous ulcers. Disease progression and treatment outcome are discussed. After symptoms persisted for more than 1 year, the patient underwent total gastrectomy with D2 lymph node dissection. The patient was diagnosed with superficial spreading cancer (ssc), accompanied by an extensive iic lesions. The progression of this patient suggests that the co-occurrence of cancerous ulcers may contribute to egc development to some extent. As is known, egc often develops into advanced gastric cancer with time. However, in our case, we observed a process during which partial cancerous changes developed into ssc over 18 months. Superficial spreading cancer should be considered an egc variant, which may have the ability to spread superficially along the stomach wall without invading the muscularis propria. But we speculate that, if gene expression changes for some reason, the malignant ssc cells may acquire the ability to grow deeply into the stomach wall. Eventually, Borrmann type iv gastric cancer may develop.

GLS/IL-12-modified Mycobacterium smegmatis as a novel anti-tuberculosis immunotherapeutic vaccine

OBJECTIVE

To study the effects and mechanisms of recombinant Mycobacterium smegmatis (rMS) carrying pZM03 (a co-expression plasmid encoding human granulysin [GLS] and murine interleukin 12 [IL-12]) on murine M. tuberculosis infection.

DESIGN

BALB/c mice infected with M. tuberculosis were treated with normal saline, M. smegmatis, pZM03 or rMS. The number of viable bacteria in the lungs and spleens were counted to observe the therapeutic effects. The levels of IL-12 and interferon-gamma (IFN-gamma) in serum, and IFN-gamma and tumour necrosis factor-alpha (TNF-alpha) released from spleen lymphocytes were detected to observe the T-helper 1 (Th1) response. Secretory IgA (SIgA) in bronchoalveolar lavage fluid was measured to observe the mucosal immunity. The lungs and spleens were prepared for pathological analysis.

RESULTS

The rMS group showed a significantly reduced number of colony-forming units compared to the other groups. The expression of GLS in the tissue, and increased levels of IL-12, IFN-gamma, TNF-alpha and SIgA, were found in the rMS group. The pathological changes in the lungs of the rMS group were localised, while those in the control group were extensive.

CONCLUSION

rMS had immunotherapeutic effects associated with a switch to the Th1 response and the antibacterial activity of GLS.

Inhibition of autophagy induced by overexpression of mda-7/interleukin-24 strongly augments the antileukemia activity in vitro and in vivo

Melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24) is a novel candidate of tumor suppressor that can selectively induce apoptosis experimentally in a spectrum of human cancer cells including leukemia cells. However, a recent study suggests that mda-7/IL-24 promotes the survival of chronic lymphocytic leukemia B-cells. In this study, we showed that mda-7/IL-24 was constitutively expressed in leukemia cell lines and primary acute myeloid leukemia samples. Using a conditionally replicating adenovirus expressing mda-7/IL-24 (ZD55-IL-24), we showed that enforced expression of mda-7/IL-24 in leukemia cells induced autophagy, which was triggered by the upregulation of Beclin-1. Immunofluorescence and coimmunoprecipitation studies suggested that mda-7/IL-24 protein interacts with Beclin-1. Class III PI3K/Beclin-1 complex was shown involved in the mda-7/IL-24-induced autophagy. Moreover, autophagy inhibition by phosphatidylinositol 3-kinase inhibitor, wortmannin, resulted in a reduced Beclin-1 expression and autophagosome formation associated with significantly enhanced cell death. Importantly, the combination of ZD55-IL-24 with wortmannin elicited a strongly enhanced antileukemia efficacy in established leukemia xenografts. These results suggest that mda-7/IL-24-induced autophagy in leukemia cells may provide survival advantage and mda-7/IL-24 combined with agents that disrupt autophagy is a promising new strategy for the treatment of leukemia.

Serine-385 phosphorylation of inwardly rectifying K+ channel subunit (Kir6.2) by AMP-dependent protein kinase plays a key role in rosiglitazone-induced closure of the K(ATP) channel and insulin secretion in rats

AIMS/HYPOTHESIS

Rosiglitazone, an insulin sensitiser, not only improves insulin sensitivity but also enhances insulin secretory capacity by ameliorating gluco- and lipotoxicity in beta cells. Rosiglitazone can stimulate insulin secretion at basal and high glucose levels via a phosphatidylinositol 3-kinase (PI3K)-dependent pathway. We hypothesised that regulation of phosphorylation of the ATP-sensitive potassium (K(ATP)) channel might serve as a key step in the regulation of insulin secretion.

METHODS

Insulin secretory responses were studied in an isolated pancreas perfusion system, cultured rat islets and MIN6 and RINm5F beta cells. Signal transduction pathways downstream of PI3K were explored to link rosiglitazone to K(ATP) channel conductance with patch clamp techniques and insulin secretion measured by ELISA.

RESULTS

Rosiglitazone stimulated AMP-activated protein kinase (AMPK) activity and induced inhibition of the K(ATP) channel conductance in islet beta cells; both effects were blocked by the PI3K inhibitor LY294002. Following stimulation of AMPK by 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), a pharmacological activator, both AICAR-stimulated insulin secretion and inhibition of K(ATP) channel conductance were unaffected by LY294002, indicating that AMPK activation occurs at a site downstream of PI3K activity. The serine residue at amino acid position 385 of Kir6.2 was found to be the substrate phosphorylation site of AMPK when activated by rosiglitazone or AICAR.

CONCLUSIONS/INTERPRETATION

Our data indicate that PI3K-dependent activation of AMPK is required for rosiglitazone-stimulated insulin secretion in pancreatic beta cells. Phosphorylation of the Ser(385) residue of the Kir6.2 subunit of the K(ATP) channel by AMPK may play a role in insulin secretion.

Phase IIb/III double-blind randomized trial of BIBW 2992, an irreversible, dual inhibitor of EGFR and HER2 plus best supportive care (BSC) versus placebo plus BSC in patients with NSCLC failing 1–2 lines of chemotherapy (CT) and erlotinib or gefitinib (LUX- Lung1): A preliminary report

8062

Background: No approved therapy exists for NSCLC patients (pts) who have failed chemotherapy (CT) and the reversible epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), erlotinib (E) or gefitinib (G). The efficacy of BIBW 2992 (Tovok), a potent, irreversible inhibitor of EGFR and human epidermal growth factor receptor 2 (HER2) with preclinical activity against the secondary resistance mutation T790M, in pts progressing after initial clinical benefit on E/G is being assessed in this randomized trial. Methods: Pts with advanced adenocarcinoma of the lung (Stage IIIB/IV; ECOG 0–2), who have failed one or two lines of CT (including platinum) and progressed following at least 12 weeks of E or G are randomized in a 2:1 ratio to receive BSC plus either oral BIBW 2992 50 mg qd or placebo until disease progression or unacceptable toxicity. Primary endpoint is overall survival, with progression-free survival, objective response and clinical benefit rate and duration, safety and quality of life being secondary endpoints. Enrollment of 400 pts is planned (HR=0.70, 85% power). An unblinded interim analysis of tumor response and safety by the independent Data Monitoring Committee (DMC) after the first 40 evaluable pts treated with BIBW 2992 will determine continuation to full accrual. Results: From May to November 2008, 145 pts have been randomized and 76 are still on treatment. Demographics (n=145): median age 59 (range: 30–82); female 68%, current/ex-smokers 38%; metastatic disease 91%, ECOG 0–1 92%; Asian origin 68%. 50% had one prior line of CT. Main prior EGFR-TKI was G in Asians (70%) and E in non-Asians (85%). 40% of pts had achieved a PR or CR on previous treatment with E/G. Duration of prior E/G treatment was >24 weeks and >48 weeks in 80% and 40% of pts, respectively. As expected, diarrhea, rash, anorexia, stomatitis, paronychia, nausea and vomiting were the most frequently observed adverse events. Conclusions: The trial is continuing recruitment after DMC review of efficacy and safety and updated demographics and blinded safety data will be reported.

[Table: see text]

Quality of life in advanced non-small cell lung cancer patients receiving first-line gefitinib monotherapy

9614

Background: Gefitinib is a potential first-line treatment option for patients with advanced non-small cell lung cancer (NSCLC), especially for patients with activating mutations in the EGFR gene. However, little is known about patient-reported health-related quality of life (HRQOL) in this patient population. The aims of this study were to explore the prognostic values of baseline HRQOL for time-to-treatment failure (TTF), as well as the predictors of repeatedly measured posttreatment HRQOL, in advanced NSCLC patients receiving first-line gefitinib. Methods: A total of 106 chemonaive patients with advanced NSCLC were enrolled in a phase II trial. Gefitinib was given at a dose of 250 mg/d. HRQOL was assessed monthly with the EuroQoL instrument (EQ-5D) and the Lung Cancer Symptom Scale (LCSS) questionnaire. Baseline HRQOL and clinical/molecular predictors of TTF were jointly examined by multiple Cox's proportional hazards model. The associations between the clinical/molecular factors and repeatedly measured posttreatment HRQOL were analyzed by fitting marginal linear regression model using the generalized estimating equations (GEE) method. Results: In this prospective study, HRQOL data were obtained from 94 patients. Baseline EQ-5D index (estimated hazard ratio = 0.286, 95% C.I.: 0.135–0.603, p = 0.001) and the presence of L858R EGFR mutation in adenocarcinoma (estimated hazard ratio = 0.520, 95% C.I.: 0.307–0.880, p = 0.015) were retained as independent prognostic factors in the final multiple Cox's proportional hazards model for TTF. According to preliminary GEE analysis of repeatedly measured posttreatment HRQOL, the patients with wild-type EGFR consistently had worse HRQOL in EQ-5D index (p < 0.0001), EQ-5D VAS score (p = 0.0002), and LCSS global score (p < 0.0001), respectively. Conclusions: In advanced NSCLC patients receiving first-line gefitinib, better baseline EQ-5D index and L858R EGFR mutation in adenocarcinoma predict longer TTF. In addition, patients with wild-type EGFR had worse posttreatment HRQOL.

No significant financial relationships to disclose.

Prognostic factors of survival in 236 advanced hepatocellular carcinoma patients enrolled in prospective clinical trials of systemic therapy

e15632

Background: Hepatocellular carcinoma (HCC) is a common malignant disease. Promising results of prospective clinical trials using systemic therapy for patients with advanced HCC are emerging. The aim of this study was to explore prognostic factors of survival in advanced HCC patients eligible for clinical trials of systemic therapy. Methods: From December 1990 to July 2005, 236 patients with unresectable HCC were enrolled into 6 phase II trials of systemic therapy using the following regimens: (1) oral etoposide + tamoxifen, (2)doxorubicin + tamoxifen, (3)IFN-α2b + doxorubicin + tamoxifen, (4)pegylated liposomal doxorubicin, (5)thalidomide, and (6)arsenic trioxide. Univariate and multivariate analyses of 23 relevant clinical characteristics/staging systems were used to identify prognostic factors of survival. Results: Baseline characteristics: median age 55; male/female: 192/44; HBsAg(+) 71%; anti-HCV(+) 30%; Okuda stage I/II/III: 42%/55%/3%; AJCC stage III/IV: 30%/61%; BCLC stage B/C/D: 1%/94%/5%; CLIP score 0–3/4–6: 70%/30%; portal vein thrombosis 53%; extrahepatic metastasis 59%; prior chemoembolization 46%. The objective response rate according to WHO criteria was 11.4%. The median overall survival was 118 days (95% CI, 103–133). In the multivariate analysis, significant predictors of a shorter overall survival were: HBsAg(+) with a hazard ratio (HR) = 1.808 (95% CI, 1.121–2.916; P= 0.015), symptomatic with HR = 1.745 (95% CI, 1.072–2.840; P= 0.025), ECOG≥2 with HR = 1.763 (95% CI, 1.040–2.988; P= 0.035), and high BCLC stage with HR = 3.282 (95% CI, 1.129–9.541; P= 0.029). Conclusions: Patients with advanced HCC who are eligible for systemic therapeutic trials have patient- and disease-related prognostic factors. Positive HBsAg, symptomatic, ECOG performance≥2, and high BCLC stage predict a shorter overall survival.

No significant financial relationships to disclose.