Cytoplasmic ERβ1 expression is associated with survival of patients with Stage IV lung adenocarcinoma and an EGFR mutation at exon 21 L858R subsequent to treatment with EGFR-TKIs

Impact of LncRNA GAS5 Genetic Variants and the Epidermal Growth Factor Receptor Phenotypes on the Clinicopathological Characteristics of Lung Adenocarcinoma Patients

The aim of the current study was to evaluate the combined effect of the single nucleotide polymorphism (SNP) in long non-coding RNA growth arrest-specific 5 (GAS5) and the phenotypes of epidermal growth factor receptor (EGFR) on the clinicopathological characteristics of lung adenocarcinoma. The present study examined the relationship between the GAS5 single-nucleotide polymorphisms (SNPs; rs145204276 Ins/Del, rs55829688 T/C) and the clinicopathological factors in 539 lung adenocarcinoma patients with or without EGFR mutations. We found that the genotype distributions of the two GAS5 SNPs between different EGFR genotypes were similar after adjusting for age, gender and smoking history. The GAS5 SNP rs145204276 Ins/Del + Del/Del illustrated a higher distribution with an advanced tumor stage (p = 0.030), larger tumor T status (p = 0.019), positive lymph node status (p = 0.014) and distal metastases (p = 0.011) in the EGFR wild type group. In the subgroup analysis of the EGFR wild type population, the presence of GAS5 SNP rs145204276 Ins/Del + Del/Del was correlated to an advanced tumor stage (p = 0.014) and distal metastases (p = 0.020) in non-smokers. In conclusion, these data indicate that the GAS5 SNP rs145204276 variant may help predict tumor stage, lymph node metastasis and distal metastases in patients with EGFR wild type lung adenocarcinoma.

Antibody Validation for Estrogen Receptor Beta

Antibodies can cross-react with proteins other than their intended targets, and antibody-based applications can, if not properly validated, lead to flawed interpretations. When evaluating 13 anti-estrogen receptor beta (ERβ) antibodies in 2017, we concluded that only one of them was specific. Applying this antibody in immunohistochemistry of over 44 different normal human tissues and 20 types of cancers revealed ERβ expression in only a few selected tissues. This aligned with mRNA evidence but contradicted a large set of published literature. ERβ protein expression continues to be reported in tissues without clear support by mRNA expression. In this chapter, we describe how ERβ antibodies can be thoroughly validated and discuss selection of well-characterized positive and negative controls. The validation scheme presented is applicable for immunohistochemistry and Western blotting. The protocol includes evaluation of mRNA evidence, use of public databases, assessment of on- and off-target binding, and an optional step for corroboration with immunoprecipitation and mass spectrometry.

Upregulation of estrogen receptor beta protein but not mRNA predicts poor prognosis and may be associated with enhanced translation in non-small cell lung cancer: a systematic review and meta-analysis

Background

An increasing number of original studies suggest that estrogen receptor beta (ERβ) expression may be related to non-small cell lung cancer (NSCLC) prognosis; however, the evidence remains inconclusive and conflicting. We aimed to systematically evaluate the expression and prognostic value of ERβ in NSCLC, and to explain the inconsistency between ERβ protein and mRNA level.

Methods

PubMed, Embase, and Web of Science databases were searched for studies (published before October 6, 2020) reporting the prognostic value of ERβ protein expression in NSCLC. The pooled hazard ratios (HRs) with 95% confidence intervals (CIs) for overall survival (OS) were calculated. Transcriptome and survival data of lung adenocarcinoma patients were obtained from public databases for differential expression and survival analyses. Immunohistochemistry (IHC) was performed to examine the ERβ protein expression in 39 NSCLC patients. Western blotting and RT-qPCR were performed to analyze ERβ expression in two paired NSCLC and normal adjacent tissue samples. The effect of methyltransferase-like 13 (METTL3) on ERβ expression was investigated in a lung cancer cell line.

Results

Meta-analysis of 23 studies with a total of 3744 patients demonstrated that high protein expression of overall ERβ and cytoplasmic ERβ indicated poor OS (HR: 1.05, 95% CI: 1.00 to 1.10; HR: 1.48, 95% CI: 1.13 to 1.95) in NSCLC. For lung adenocarcinoma especially, high protein expression of both overall/cytoplasmic ERβ and nuclear ERβ suggested poor OS (HR: 1.54, 95% CI: 1.05 to 2.25; HR: 1.36, 95% CI: 1.03 to 1.80). Bioinformatics analysis indicated the expression of ERβ mRNA was not associated with the prognosis of lung adenocarcinoma. Analysis of public databases showed that ERβ mRNA is not highly expressed in tumor tissues, however, IHC results revealed that ERβ protein is highly expressed in NSCLC tissues. We validated this inconsistency in ERβ expression in paired tumors and normal adjacent tissues from patients. Moreover, METTL3 knockdown in the A549 cell line downregulated ERβ protein expression but not ERβ mRNA expression.

Conclusions

Our study elucidated the inconsistency between ERβ protein and mRNA expression levels and their prognostic values. The results indicated that METTL3-driven enhanced translation in NSCLC may cause this inconsistency.