The prevalence and prognostic significance of estrogen receptor beta expression in non-small cell lung cancer

ERβ overexpression may not be a direct prognostic factor in patients with NSCLC: A meta-analysis

BACKGROUND

Overall survival of non-small cell lung cancer (NSCLC) patients remains disappointingly low. The estrogen receptor (ER) was considered a promising therapeutic target for NSCLC. Numerous studies have linked expression of ERβ to lung cancer outcome. However, results are conflicting regarding the association of ERβ with surviving lung cancer.

METHOD

The aim of this meta-analysis was to evaluate the prognostic aspect of ERβ expression on survival among NSCLC patients. We performed a final analysis of prognostic value of overexpression ERβ on 3500 patients from 18 evaluable studies (from January 1, 2000 to May 1, 2021). The reference category is specified as low ERβ expression levels. Summarized hazard ratios were calculated.

RESULTS

Our study showed that the pooled hazard ratios of ERβ overexpression for overall survival in NSCLC was 0.81 (95% confidence interval (CI): 0.64-1.02, P = 0.07) by univariate analysis and 1.06 (95% CI: 0.83-1.36, P = 0.63) by multivariate analysis. Pooled hazard ratio by univariate analysis in Asian studies was 0.73 (95%CI: 0.59-0.89, P = 0.002). Pooled hazard ratio by univariate analysis was 0.75 (95% CI: 0.61-0.93, P = 0.009) from seven studies reported for nuclear ERβ. No significant results were found in subgroups by multivariate analysis. No significant results were found in studies outside Asia or in studies reported for cytoplasmic ERβ.

CONCLUSION

Our results suggested that expression of ERβ might not be a direct prognostic factor for NSCLC patients. More detailed prospective studies are needed to identify direct prognostic factors in these patients.

Estrogen receptor beta promotes lung cancer invasion via increasing CXCR4 expression

Lung cancer is one of the most lethal malignant tumors in the world. The high recurrence and mortality rate make it urgent for scientists and clinicians to find new targets for better treatment of lung cancer. Early studies indicated that estrogen receptor β (ERβ) might impact the progression of non-small-cell lung cancer (NSCLC). However, the detailed mechanisms, especially its linkage to the CXCR4-mediated cell invasion, remain unclear. Here we found that ERβ could promote NSCLC cell invasion via increasing the circular RNA (circRNA), circ-TMX4, expression via directly binding to the 5′ promoter region of its host gene TMX4. ERβ-promoted circ-TMX4 could then sponge and inhibit the micro RNA (miRNA, miR), miR-622, expression, which can then result in increasing the CXCR4 messenger RNA translation via a reduced miRNA binding to its 3′ untranslated region (3′UTR). The preclinical study using an in vivo mouse model with orthotopic xenografts of NSCLC cells confirmed the in vitro data, and the human NSCLC database analysis and tissue staining also confirmed the linkage of ERβ/miR-622/CXCR4 signaling to the NSCLC progression. Together, our findings suggest that ERβ can promote NSCLC cell invasion via altering the ERβ/circ-TMX4/miR-622/CXCR4 signaling, and targeting this newly circ-TMX4/miR-622/CXCR4 signaling may help us find new treatment strategies to better suppress NSCLC progression.

Estrogen Receptor ß in Cancer: To ß(e) or not to ß(e)?

Estrogen receptors (ERs) are known to play an important role in the proper development of estrogen-sensitive organs, as well as in the development and progression of various types of cancer. ERα, the first ER to be discovered, has been the focus of most cancer research, especially in the context of breast cancer. However, ERβ expression also plays a significant role in cancer pathophysiology, notably its seemingly protective nature and loss of expression with oncogenesis and progression. Although ERβ exhibits antitumor activity in breast, ovarian, and prostate cancer, its expression is associated with disease progression and worse prognosis in lung cancer. The function of ERβ is complicated by the presence of multiple isoforms and single nucleotide polymorphisms, in addition to tissue-specific functions. This mini-review explores current literature on ERβ and its mechanism of action and clinical implications in breast, ovarian, prostate, and lung cancer.

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.

Diagnostic and therapeutic ERβ, HER2, BRCA biomakers in the histological subtypes of lung adenocarcinoma according to the IASLC/ATS/ERS classification

Several studies revealed that non-small cell lung cancers (NSCLCs) frequently express ER, PR, HER2 and carry BRCA mutation. However, these markers in histological subtypes of lung adenocarcinoma have not been thoroughly investigated. We retrospectively evaluated a total of 640 lung adenocarcinoma samples for ERα, ERβ, PR and HER2 expression by immunohistochemistry and western-blotting, for EGFR and BRCA mutation by real-time PCR and sequencing. Furthermore, HER2 amplification and mutation were explored in samples harboring immunopositivity HER2 using fluorescence in situ hybridization and real-time PCR, respectively. The micropapillary and invasive mucinous predominant adenocarcinoma were frequently detected the higher level of cytoplasmic ERβ (64.9% and 56.6%), HER2 (68.1% and 60.1%) protein expression. But, amplification of HER2 was detected in only three cases (3/110, 2.7%) and 26 HER2 mutations in 110 cases were identified (23.6%) in the HER2 immunopositivity patients. Logistic regression analysis showed that cytoplasmic ERβ (P = 0.032) and HER2 (P = 0.015) expression were independently associated with EGFR mutation. 8 patients (8/640, 1.25%) harbored pathogenic BRCA mutations, 6 with germline BRCA mutations and 2 with somatic BRCA1 mutations were detected with lacking ERβ, PR and HER2 expression. Acinar predominant adenocarcinoma had the higher percentage of BRCA mutations than other subtypes. A systematic examination of ERβ, HER2 and BRCA biomarkers could potentially be useful to diagnosis and identify patients with the histological subtypes of lung adenocarcinoma, who might benefit from the further individualized treatment of anti-hormone, anti-HER2 and/or PARP inhibitors therapeutics.