ERα phenotype, estrogen level, and benzo[a]pyrene exposure modulate tumor growth and metabolism of lung adenocarcinoma cells

ERα-dependent estrogen-TNFα signaling crosstalk increases cisplatin tolerance and migration of lung adenocarcinoma cells

Lung adenocarcinoma is the most common type of lung cancer in women. Our previous studies demonstrated that 17β-estradiol (E2) promoted lung adenocarcinoma cell proliferation and tumor growth through estrogen receptor ERα. Transcriptomic analysis suggested that E2 potentiated TNFα-NFκB signaling in ERα-expressing lung adenocarcinoma cells. This study further demonstrated that E2 increased TNFα receptor expression and TNFα-triggered NFκB activity in ERα-expressing cells. E2-activated ERα had no physical association with NFκB p65/p50 heterodimer but facilitated TNFα-initiated IκBα degradation, NFκB nuclear translocation, and S468/S536 phosphorylation of p65 essential for NFκB activity. While knockdown of ERα prevented E2 from boosting NFκB activity, antiestrogen ICI 182,780 stimulated NFκB activity like E2. Inhibition of GSK3β hampered E2:ERα-promoted NFκB activity and abolished S468 phosphorylation of p65, suggesting that GSK3β played a role in the E2-TNFα signaling crosstalk. In ERα-expressing cells, E2 and TNFα synergistically regulated many genes that were not typically responsive to either E2 or TNFα. Functional analysis of microarray data inferred that E2/TNFα-induced transcriptomic changes improved cell survival and movement. Viability and colony formation assays validated that E2 and TNFα together increased cisplatin tolerance of ERα-expressing cells. Wound healing assays also confirmed that E2/TNFα cotreatment increased cell migration in an ERα-dependent manner. E2/TNFα-induced dysregulation of genes such as cell survival and movement-associated genes, proto-oncogenes, metallothioneins and histone core genes was correlated with poor overall survival in patients. In summary, E2 and TNFα engaged in an ERα-dependent positive crosstalk in lung adenocarcinoma cells, consequently increasing NFκB activation, cisplatin tolerance and cell migration and worsening prognosis.

Reproductive factors and lung cancer risk: a comprehensive systematic review and meta-analysis

BACKGROUND

A number of studies have investigated the association between reproductive factors and lung cancer risk, however findings are inconsistent. This meta-analysis aimed to evaluate the association between female reproductive factors and lung cancer risk.

METHODS

We conducted a comprehensive systematic search to identify relevant and eligible studies published before 18th December 2019. Inter-study heterogeneity was assessed using the Q test and I2 statistic. Based on the heterogeneity of each reproductive factor, fixed or random effects models were used to calculate the summary odds ratios (ORs) and 95% confidence intervals (CIs). Subgroup analyses by study design, lung cancer subtypes, smoking status, and ethnicity were also performed.

RESULTS

A total of 66 studies with 20 distinct reproductive factors were included in this meta-analysis. Comparing the highest and lowest categories (reference) of each reproductive factor, parity (OR = 0.83, 95% CI = 0.72-0.96), menstrual cycle length (OR = 0.79, 95% CI = 0.65-0.96), and age at first birth (OR = 0.85, 95% CI = 0.74-0.98), were significantly associated with a lower risk of overall lung cancer. On the contrary, non-natural menopause was significantly associated with higher lung cancer risk (OR = 1.52, 95% CI = 1.25-1.86). Among never-smokers, a significant negative association was found between parity and lung cancer risk. Both parity and non-natural menopause were statistically significant in case-control studies.

CONCLUSION

These results suggest that certain reproductive factors may be associated with lung cancer risk. Future studies should further validate the associations, and investigate the underlying mechanisms.

Induction of proliferative and mutagenic activity by benzo(a)pyrene in PC-3 cells via JAK2/STAT3 pathway

Environmental carcinogen benzo(a)pyrene (BaP) is a representative compound of polycyclic aromatic hydrocarbons (PAHs). BaP is strongly associated with prostate carcinogenesis. However, the molecular mechanism of BaP in development of prostate carcinoma remains largely unknown. The aim of this study was to investigate the effect and mechanism of BaP on the development in prostate cancer. PC-3 cells were exposed to different concentrations of BaP for 24, 48, 72 h, respectively. We analyzed the effect of BaP on PC-3 cell viability, cell cycle, DNA strand breaks, mutagenic activity, and migration. The expression of associated regulatory genes and the effect of JAK2/STAT3 signaling were also measured to explore the relationships among BaP metabolism, the JAK2/STAT3 pathway and proliferative activity in PC-3 cells. We observed significant effects on proliferation, DNA strand breaks and mutagenic activity after BaP exposure in PC-3 cells, and inhibitors of CYP1 and the AhR transcription factor α -naphthoflavone (ANF) and CH223191 treatment clearly reduced both cell survival and mutagenesis associated with BaP exposure. Reduction in G0-G1 phase population and elevation in S phase were observed after BaP exposure. Migratory cells for PC-3 were significantly increased. The results were further confirmed by the expression of mRNA levels in the significant increments of Snail, Slug, MMP-9, CYP1A1, CYP1B1, CycilnD1, CDK4 and significant reduction of E-cadherin. Significant enhancements were found in the expression of JAK2, STAT3 after BaP treatment. Additionally, activator IL-6 significantly enhanced the effect of BaP on cell survival, mutagenic activity, Cyclin D1, CDK4, Snail, and JAK2/STAT3 expression in PC-3 cells. Significant reductions in cell survival, mutagenic activity, Cyclin D1, CDK4, Snail, and JAK2/STAT3 expression were found after inhibitor AG490, ANF and CHJ223191 treatment. These findings reveal that BaP enhances the proliferative and mutagenic activity via JAK2-STAT3 pathway in PC-3 cells, and provide the additional evidence to understand the crucial role of BaP in prostate cancer carcinogenesis.

Inversion of natural immuno-hormonal interactions under influence of antibodies against environmental chemical carcinogens

In this article we present a hypothesis that interactions between sex hormones and specific antibodies change inversely in presence of antibodies against environmental carcinogens. Natural occurrence antibodies to estradiol (E2) and progesterone (Pg) do not influence on E2 concentration, but antibodies to Pg increase Pg concentration in blood serum of postmenopausal healthy women with low levels of antibodies against benzo[a]pyrene (Bp). Thereby natural occurrence antibodies to Pg inhibit the promotion of breast carcinogenesis. Antibodies to E2 and Pg increase E2 concentration but decrease Pg concentration when the levels of antibodies to Bp are high. Therefore, antibodies against Bp switch hormonal effects of antibodies to E2 and Pg from the increase of Pg concentration to the increase of E2, thus stimulating breast cancer promotion. These immuno-hormonal interactions are weaker in breast cancer patients, probably due to corresponding anti-idiotypic antibodies.

Immunomodulation of carcinogens-induced steroids-dependent human diseases

The experimental and clinical data about antibodies against environmental chemical carcinogens and endogenous steroids are represented. The conception of immunomodulation of carcinogens- and steroids-dependent human diseases is proposed. It is postulated that antibodies to polycyclic aromatic hydrocarbons and heterocyclic amines in cooperation with antibodies to cholesterol, sex hormones, mineralo- and glucocorticoids stimulate or inhibit cancer, malformation, cardiovascular and autoimmune diseases depending on their personal combination. It is recommended to use immunoassay of these antibodies for the human diseases prediction. The alternative approaches for prevention using the probiotics transformed by anti-carcinogen antibodies are substantiated.

Immunization against environmental chemical carcinogens: Pro and contra

The problems of immunoprotection from the environmental chemical carcinogens are discussed. The main experimental argument pro active immunization against carcinogens is a possibility of specific mucosal antibodies (Abs) to inhibit the penetration of carcinogens from environment and to stimulate its excretion with the following decreasing of carcinogen-DNA adducts levels. Hypothesis of cancer immunostimulation after active immunization against carcinogens is based on a high cancer risk in persons with high levels of serum Abs specific to environmental carcinogens coupled with high levels of Abs to endogenous steroids stimulating the proliferation of target cells, for example, Abs to benzo[a]pyrene together with Abs to estradiol. The active immunization could increase the cancer risk much more in those persons. The passive immunization could be an alternative safe approach to avoid this problem.

Smoking, Sex, and Non-Small Cell Lung Cancer: Steroid Hormone Receptors in Tumor Tissue (S0424)

Background

To what extent steroid hormones contribute to lung cancer in male and female never smokers and smokers is unclear. We examined expression of hormone receptors in lung tumors by sex and smoking.

Methods

Patients with primary non-small cell lung cancer were recruited into an Intergroup study in the United States and Canada, led by SWOG (S0424). Tumors from 813 cases (450 women and 363 men) were assayed using immunohistochemistry for estrogen receptor (ER)-α, ER-β, progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Linear regression was used to examine differences in expression by sex and smoking status. Cox proportional hazard models were used to estimate survival associated with the receptors. All statistical tests were two-sided.

Results

In ever smokers, postmenopause and oral contraceptive use were associated with lower nuclear ER-β (P = .02) and total (nuclear + cytoplasmic) PR expression (P = .02), respectively. Women had lower cytoplasmic ER-α (regression coefficient [β], or differences in H-scores = -15.8, P = .003) and nuclear ER-β (β = -12.8, P = .04) expression than men, adjusting for age, race, and smoking. Ever smokers had both higher cytoplasmic ER-α (β = 45.0, P < .001) and ER-β (β = 25.9, P < .001) but lower total PR (β = -42.1, P < .001) than never smokers. Higher cytoplasmic ER-α and ER-β were associated with worse survival (hazard ratio = 1.73, 95% confidence interval [CI] = 1.15 to 2.58, and HR = 1.59, 95% CI = 1.08 to 2.33, respectively; quartiles 4 vs 1).

Conclusions

Lower expression of nuclear ER-β in women supports the estrogen hypothesis in lung cancer etiology. Increasing cytoplasmic ER-α and ER-β and decreasing PR protein expression may be mechanisms whereby smoking disrupts hormone pathways.

Health risk of metal exposure via inhalation of cigarette sidestream smoke particulate matter

Cigarette sidestream smoke particulate matter (CSSP) is a major source of airborne metals in the indoor environment. However, the health impacts of inhalation of CSSP-bound metals are rarely studied. In this study, we quantify the amount of 37 metals discharged through CSSP from a leading Taiwan brand of cigarette, Long Life. We also estimate cancer and non-cancer risks due to inhalation of these metals and investigate possible modes of toxic action. Long Life CSSP exhibits a distinctive carcinogenic metal profile compared with Western brands. When released to a 60-m³ poorly ventilated room, Long Life CSSP metals increase the risk for cancer by a 9.26 or 20.90 in a million chance and the hazard quotient for non-cancer toxicity by 0.496 or 0.286 per cigarette depending on risk estimation system. Cd accounts for more than 90% and 80% of cancer and non-cancer risk, respectively. Long Life CSSP also contains considerable amounts of Al, Ba, and Fe. Metals are not responsible for CSSP-induced cytotoxicity, oxidative stress, and transactivation activity of AhR, Nrf2, and ERα. However, they diminish resveratrol-activated Nrf2 activity and downstream antioxidant gene expression in low-AhR-expressing lung cells. Our results suggest that chronic exposure to Long Life CSSP elevates Cd-associated cancer and non-cancer risks. Furthermore, exposure to Long Life CSSP metals may impair Nrf2-mediated antioxidant protection.

A Single-Center Retrospective Study of Patients with Double Primary Cancers: Breast Cancer and EGFR-Mutant Non-Small Cell Lung Cancer

BACKGROUND

Second primary malignancies (SPM) in the lung are not common in breast cancer (BC) patients. EGFR-mutant lung cancer (LC) is a separate molecular subset, and the co-existence of EGFR-mutant LC and BC has not been explored. We hypothesized that EGFR-mutant LC patients could have higher rates of primary BC than those with EGFR-wild type (WT).

METHODS

We collected data on clinical and molecular characteristics and outcomes of female patients with LC and a previous or simultaneous history of primary BC treated in our hospital from 2008 to 2014.

RESULTS

Data on treatment, follow-up, and EGFR mutation status were available for 356 patients. 17.7% (11/62) of patients with EGFR mutations had BC, compared to 1.02% (3/294) of EGFR-WT patients (p < 0.001). Both tumors were metachronous in 81.8%, with LC diagnosed 9 years after the diagnosis of BC. 5 of the 6 (83.3%) BC patients treated with radiotherapy developed LC in an area within the radiation field. No EGFR mutations were detected in BC tissue and no HER2 expression was detected in LC samples.

CONCLUSION

SPM in the lung and breast occur more frequently among EGFR-mutant compared to EGFR-WT LC patients. Radiotherapy for BC may increase the risk of developing primary LC.

Serum VEGF Level Is Different in Adolescents Smoking Waterpipe versus Cigarettes: The Irbid TRY

Waterpipe (Wp) use is associated with most devastating diseases and particularly popular among adolescents. Vascular endothelium growth factor (VEGF) is essential for generating new vessels. The effect of smoking tobacco on VEGF is controversial and unknown among adolescents. Therefore, the current study compared serum VEGF in adolescents smoking cigarettes (Cg) only (9.3%), Wp only (19.6%), and dual (Wp and Cg) (36.4%) versus nonsmokers (34.6%) in adolescents. A self-reported questionnaire and enzyme-linked immunosorbent assay (ELISA) were used to obtain smoking status and serum VEGF, respectively, in 475 (age: 14.6 ± 1.0 years) boys (n = 263) and girls (n = 212) from Irbid, Jordan. The analysis showed that smoking status (R² = 0.021; p = 0.001) and gender (R² = 0.035; p = 0.000) can predict VEGF. Furthermore, 2-way-ANCOVA revealed that VEGF was lower in the dual cohort versus the Cg (33.4%; p = 0.04) and nonsmoker (29.6%; p = 0.003) cohorts; VEGF in smokers, was lower (33.6%; p = 0.04) in the Wp versus nonsmokers in the boys but not the girls. These results are unique and suggest that smoking lowers VEGF, which might adversely affect vascular growth and function. This is alarming given that adolescents are still in the development stage and smoking, particularly Wp, is popular among them. Therefore, interventions targeting smoking among schoolchildren are urgently needed to avoid the negative effects of smoking, especially on vascular health.

Estrogen and cigarette sidestream smoke particulate matter exhibit ERα-dependent tumor-promoting effects in lung adenocarcinoma cells

Estrogen and secondhand smoke are key risk factors for nonsmoking female lung cancer patients who frequently have lung adenocarcinoma and show tumor estrogen receptor α (ERα) expression. We speculated that estrogen and secondhand smoke might cause harmful effects via ERα signaling. Our results showed that 17β-estradiol (E2), the primary form of endogenous estrogen, exacerbated proliferation, migration, and granzyme B resistance of lung adenocarcinoma cells in an ERα-dependent manner. Cigarette sidestream smoke particulate matter (CSSP), the major component of secondhand smoke, could activate ERα activity dose dependently in human lung adenocarcinoma cells. The estrogenic activity of CSSP was abolished by an ERα-selective antagonist. CSSP regulated the nuclear entry, phosphorylation, and turnover of ERα similarly to E2. Furthermore, CSSP enhanced E2-stimulated ERα activity and Ser118 phosphorylation even when ERα became saturated with E2. Activation of ERα by CSSP required GSK3β activity, but not involving polycyclic aromatic hydrocarbons, reactive oxygen species, calcium, epidermal growth factor receptor, and PI3K/Akt. Although CSSP possessed cytotoxicity, ERα-expressing cells grew and migrated faster than nonexpressing cells on recovery from CSSP exposure as observed in E2-pretreated cells. Knockdown of ERα by siRNA diminished E2- and CSSP-stimulated cell migration. Twenty-one genes, including SERPINB9, were identified to be upregulated by both E2 and CSSP via ERα. Increased SERPINB9 expression was accompanied with increased resistance to granzyme B-mediated apoptosis. This study demonstrates that estrogen has ERα-dependent tumor-promoting activity. CSSP acts like estrogen and shows a potential to enhance estrogen-induced ERα action.

Dioxin and estrogen signaling in lung adenocarcinoma cells with different aryl hydrocarbon receptor/estrogen receptor α phenotypes

Evidence suggests that estrogen affects the pulmonary response to carcinogenic pollutants, such as dioxins. In this study, we examined dioxin and estrogen signaling cross-talk in lung adenocarcinoma cell lines that were engineered to exhibit different aryl hydrocarbon receptor (AhR)/estrogen receptor (ER) α phenotypes. Data showed that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) weakly antagonized estrogen-activated ERα activity in cells expressing abundant ERα, but little AhR. Increase of AhR expression or presence of a dioxin-responsive element in proximity silenced the antiestrogenic effect of TCDD. AhR was bound to dioxin-responsive element and transcriptionally active in both TCDD-untreated and -treated lung adenocarcinoma cells. 17β-estradiol (E2) reduced basal and TCDD-induced AhR activity only in ERα-positive cells. AhR and ERα exhibited a protein-protein interaction in the presence of E2. Cotreatment with TCDD moderated this protein interaction. Colocalization of ERα and AhR at the estrogen-responsive site under E2 and TCDD/E2 treatments implied that E2 ∣ ERα might hijack AhR away from the dioxin-responsive site. Increasing the relative expression of AhR to ERα counteracted inhibition of AhR activity by E2 ∣ ERα. When AhR and ERα were both highly expressed, TCDD and E2 up-regulated expression of dual-responsive genes cytochrome P450 (CYP) 1A1 and CYP1B1 in a cumulative manner, increasing the danger of metabolic activation of carcinogens. Whereas TCDD ∣ AhR and E2 ∣ ERα appeared to regulate CYP1B1 separately through their binding sites, E2 ∣ ERα increased the TCDD responsiveness and mRNA expression of CYP1A1 in a noncanonical way. In conclusion, AhR/ERα expression pattern, estrogen level, and promoter context determine the genomic action of dioxin in lung adenocarcinoma cells.

Menstrual factors, reproductive factors and lung cancer risk: a meta-analysis

BACKGROUND AND OBJECTIVE

Epidemiological studies have suggested that menstrual and reproductive factors may influence lung cancer risk, but the results are controversial. We therefore carried out a meta-analysis aiming to examine the associations of lung cancer in women with menstrual and reproductive factors.

METHODS

Relevant studies were searched from PubMed database, CNKI, WANFANG DATA and VIP INFORMATION up to January 2012, with no language restrictions. References listed from selected papers were also reviewed. We included studies that reported the estimates of relative risks (RRs) with 95% confidence intervals (CIs) for the association between menstrual and reproductive factors and lung cancer risk. The pooled RRs were calculated after the heterogeneity test with the software Stata 11, and publication bias and sensitivity were evaluated at the same time.

RESULTS

Twenty-five articles, representing 24 independent studies, were included in this meta-analysis. Older age at menarche in North America women (RR=0.83; 95%CI: 0.73-0.94) was associated with a significant decreased risk of lung cancer. Longer length of menstrual cycle was also associated with decreased lung cancer risk (RR=0.72; 95%CI: 0.57-0.90). Other exposures were not significantly associated.

CONCLUSIONS

Our analysis provides evidence of the hypothesis that female sex hormones influence the risk of lung cancer in women, yet additional studies are warranted to extend this finding and to clarify the underlying mechanisms.

Estrogen and cancer

Estrogen exhibits a broad spectrum of physiological functions ranging from regulation of the menstrual cycle and reproduction to modulation of bone density, brain function, and cholesterol mobilization. Despite the beneficial actions of endogenous estrogen, sustained exposure to exogenous estrogen is a well-established risk factor for various cancers. We summarize our current understanding of the molecular mechanisms of estrogen signaling in normal and cancer cells and discuss the major challenges to existing antiestrogen therapies.

The role of Transposable Elements in shaping the combinatorial interaction of Transcription Factors

Background

In the last few years several studies have shown that Transposable Elements (TEs) in the human genome are significantly associated with Transcription Factor Binding Sites (TFBSs) and that in several cases their expansion within the genome led to a substantial rewiring of the regulatory network. Another important feature of the regulatory network which has been thoroughly studied is the combinatorial organization of transcriptional regulation. In this paper we combine these two observations and suggest that TEs, besides rewiring the network, also played a central role in the evolution of particular patterns of combinatorial gene regulation.

Results

To address this issue we searched for TEs overlapping Estrogen Receptor α (ERα) binding peaks in two publicly available ChIP-seq datasets from the MCF7 cell line corresponding to different modalities of exposure to estrogen. We found a remarkable enrichment of a few specific classes of Transposons. Among these a prominent role was played by MIR (Mammalian Interspersed Repeats) transposons. These TEs underwent a dramatic expansion at the beginning of the mammalian radiation and then stabilized. We conjecture that the special affinity of ERα for the MIR class of TEs could be at the origin of the important role assumed by ERα in Mammalians. We then searched for TFBSs within the TEs overlapping ChIP-seq peaks. We found a strong enrichment of a few precise combinations of TFBS. In several cases the corresponding Transcription Factors (TFs) were known cofactors of ERα, thus supporting the idea of a co-regulatory role of TFBS within the same TE. Moreover, most of these correlations turned out to be strictly associated to specific classes of TEs thus suggesting the presence of a well-defined "transposon code" within the regulatory network.

Conclusions

In this work we tried to shed light into the role of Transposable Elements (TEs) in shaping the regulatory network of higher eukaryotes. To test this idea we focused on a particular transcription factor: the Estrogen Receptor α (ERα) and we found that ERα preferentially targets a well defined set of TEs and that these TEs host combinations of transcriptional regulators involving several of known co-regulators of ERα. Moreover, a significant number of these TEs turned out to be conserved between human and mouse and located in the vicinity (and thus candidate to be regulators) of important estrogen-related genes.