Serum neuregulin 1 in relation to ventricular function and subclinical atherosclerosis in type 2 diabetes patients

BACKGROUND AND AIMS

Neuregulin 1 (NRG-1) is one of the members of the epidermal growth factors proteins. The present study provides novel insights into the relationship between serum levels of NRG-1 and insulin resistance, subclinical atherosclerosis and cardiac dysfunction that occur in type 2 diabetes (T2D).

METHODS

The study included 50 patients with T2D and 40 healthy age- and gender-matched controls. Serum NRG-1 was measured using ELISA. Glycemic parameters, lipid profile and insulin resistance were assessed. Trans-thoracic echocardiography and carotid intima media thickness (CIMT) were studied for all study subjects.

RESULTS

T2D patients had significantly lower serum NRG-1 levels than controls. Serum NRG-1 was negatively correlated with age, fasting blood glucose, HbA1c, insulin resistance, blood urea, serum creatinine and LDL-C, and positively correlated with HDL-C, eGFR and CIMT. Regarding echocardiographic variables, serum NRG-1 was found to correlate positively with left ventricular global longitudinal strain and negatively with E/Ea ratio. NRG-1 was found to predict subclinical atherosclerosis in type 2 diabetes patients at a cut-off value<108.5pg/ml with 78% sensitivity and 80% specificity.

CONCLUSIONS

A robust relationship was found between serum NRG-1 levels and hyperglycemia, insulin resistance, subclinical atherosclerosis, and cardiac dysfunction in patients with type 2 diabetes. These results shed light on a possible role of NRG-1 as a potential noninvasive biomarker for detection of cardiometabolic risk in T2D.

Neuregulin1 types mRNA level changes in autism spectrum disorder, and is associated with deficit in executive functions

BACKGROUND

Autism spectrum disorder (ASD) is a pediatric heterogeneous psychiatric and neurodevelopmental disorder with social and communication deficits, language impairment and ritualistic or repetitive behaviors. ASD has significant genetic bases but candidate genes and molecular mechanisms of disorder are not clarified. Neuregulin1 (NRG1) gene, located in 8p12 is involved in development of central nervous system and was indicated as candidate gene in schizophrenia.

METHODS

mRNA level of types I, II and III of NRG1 gene were studied in peripheral blood of 1540 ASD patients (IQ > 70) and 1490 control children by quantitative Real Time PCR. Also three domains of executive functions (working memory, response inhibition and vigilance) were examined in all subjects.

FINDINGS

All three types were significantly down regulated in ASD patients. Significant deficiencies in executive functions (EF) were found in ASD patients. EF deficiencies mostly were associated with down expression of mRNA level of types I and III. Also correlations were found between NRG1 expression with gender and severity of ASD symptoms.

INTERPRETATIONS

Findings primarily have been suggested involvement of NRG1 in etiology of ASD. Also correlation of NRG1 mRNA level with EF deficiencies could shed lights on EF mechanisms and may suggest targeted treatments to improve particular executive functions. FUND: Young researchers and elites club funded the project due to the annual grant of special talents of Club that gave to Arvin Haghighatfard.

Chronic administration of calcitriol enhanced neuregulin-1/ErbB signaling in rat myocardium

Although emerging evidence suggests that vitamin D has beneficial effects in the cardiovascular health, the underlying mechanisms are far from fully elucidated. Given the indispensable role of neuregulin-1 (NRG1)/ErbB signaling in the cardiovascular system, the present study investigated the influences of prolonged administration of calcitriol, the active form of vitamin D, on the NRG1/ErbB system. We examined the protein expression of NRG1, ErbB receptors (ErbB2 and ErbB4) and their phosphorylated forms in the myocardium of rats following 6-week administration of calcitriol (50 ng/kg/day or 100 ng/kg/day). We further assessed the myocardial vitamin D receptor (VDR) to confirm the effect of calcitriol treatment. Additionally, serum neuregulin-1 level was also analyzed. Generally, calcitriol enhanced myocardial VDR expression and NRG1/ErbB signaling. Calcitriol increased NRG1 protein level at the higher dose, while both doses promoted ErbB2 and phosphorylated ErbB2 expression. Although calcitriol has no significant influence on ErbB4 expression, phosphorylated ErbB4 receptors were enhanced at the higher dose. Furthermore, the serum neuregulin-1 concentration was increased at both doses. Overall, our data firstly showed that chronic calcitriol administration enhanced NRG1/ErbB signaling in the heart, indicating a novel mechanism underlying the cardiac effects of vitamin D.

Combined Analysis of Plasma Amphiregulin and Heregulin Predicts Response to Cetuximab in Metastatic Colorectal Cancer

Background

Amphiregulin, a ligand of the epidermal growth factor receptor (EGFR), is associated with the efficacy of cetuximab, an antibody against EGFR, as treatment for colorectal cancer (CRC). In contrast, the HER3 ligand heregulin correlates with cetuximab resistance. In this study, we evaluated how the combined levels of circulating amphiregulin and heregulin affect clinical outcomes in patients who receive cetuximab as therapy against advanced CRC.

Methods

Plasma levels of amphiregulin and heregulin were measured by enzyme-linked immunosorbent assay in 50 patients with CRC in a training cohort, and in 10 patients in a validation cohort. The combined expression was then assessed with clinical outcome after receiver operating characteristics analysis.

Results

Overall response rate was 26%, and median progression-free survival was 110 days in the training cohort. Patients with high amphiregulin and low heregulin had significantly higher objective response rate at 58% and significantly longer progression-free survival of 216 days. This result was confirmed in the validation cohort.

Conclusion

A subgroup of CRC patients with high amphiregulin and low heregulin respond to cetuximab therapy better than other patients.

Clinical Translation and Validation of a Predictive Biomarker for Patritumab, an Anti-human Epidermal Growth Factor Receptor 3 (HER3) Monoclonal Antibody, in Patients With Advanced Non-small Cell Lung Cancer

Background

During early clinical development, prospective identification of a predictive biomarker and validation of an assay method may not always be feasible. Dichotomizing a continuous biomarker measure to classify responders also leads to challenges. We present a case study of a prospective–retrospective approach for a continuous biomarker identified after patient enrollment but defined prospectively before the unblinding of data. An analysis of the strengths and weaknesses of this approach and the challenges encountered in its practical application are also provided.

Methods

HERALD (NCT02134015) was a double-blind, phase 2 study in patients with non-small cell lung cancer (NSCLC) randomized to erlotinib with placebo or with high or low doses of patritumab, a monoclonal antibody targeted against human epidermal growth factor receptor 3 (HER3). While the primary objective was to assess safety and progression-free survival (PFS), a secondary objective was to determine a single predictive biomarker hypothesis to identify subjects most likely to benefit from the addition of patritumab. Although not identified as the primary biomarker in the study protocol, on the basis of preclinical results from 2 independent laboratories, expression levels of the HER3 ligand heregulin (HRG) were prospectively declared the predictive biomarker before data unblinding but after subject enrollment. An assay to measure HRG mRNA was developed and validated. Other biomarkers, such as epidermal growth factor receptor (EGFR) mutation status, were also evaluated in an exploratory fashion. The cutoff value for high vs. low HRG mRNA levels was set at the median delta threshold cycle. A maximum likelihood analysis was performed to evaluate the provisional cutoff. The relationship of HRG values to PFS hazard ratios (HRs) was assessed as a measure of internal validation. Additional NSCLC samples were analyzed to characterize HRG mRNA distribution.

Results

The subgroup of patients with high HRG mRNA levels (“HRG-high”) demonstrated clinical benefit from patritumab treatment with HRs of 0.37 (P = 0.0283) and 0.29 (P = 0.0027) in the high- and low-dose patritumab arms, respectively. However, only 102 of the 215 randomized patients (47.4%) had sufficient tumor samples for HRG mRNA measurement. Maximum likelihood analysis showed that the provisional cutoff was within the optimal range. In the placebo arm, the HRG-high subgroup demonstrated worse prognosis compared with HRG-low. A continuous relationship was observed between increased HRG mRNA levels and lower HR. Additional NSCLC samples (N = 300) demonstrated a similar unimodal distribution to that observed in this study, suggesting that the defined cutoff may be applicable to future NSCLC studies.

Conclusions

The prospective–retrospective approach was successful in clinically validating a probable predictive biomarker. Post hoc in vitro studies and statistical analyses permitted further testing of the underlying assumptions. However, limitations of this analysis include the incomplete collection of adequate tumor tissue and a lack of stratification. In a phase 3 study, findings are being confirmed, and the HRG cutoff value is being further refined.

ClinicalTrials.gov Number

NCT02134015.

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High heregulin levels predict benefit from patritumab treatment in patients with NSCLC.

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A prospective–retrospective approach provisionally validated a predictive biomarker.

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Post hoc analyses can be used to test underlying assumptions in biomarker validation.

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The median may be a reasonable initial cutoff for a unimodal continuous biomarker.