Expression of vitamin D receptor in lung cancer

Targeting Nuclear Receptors in Lung Cancer—Novel Therapeutic Prospects

Lung cancer, the second most commonly diagnosed cancer, is the major cause of fatalities worldwide for both men and women, with an estimated 2.2 million new incidences and 1.8 million deaths, according to GLOBOCAN 2020. Although various risk factors for lung cancer pathogenesis have been reported, controlling smoking alone has a significant value as a preventive measure. In spite of decades of extensive research, mechanistic cues and targets need to be profoundly explored to develop potential diagnostics, treatments, and reliable therapies for this disease. Nuclear receptors (NRs) function as transcription factors that control diverse biological processes such as cell growth, differentiation, development, and metabolism. The aberrant expression of NRs has been involved in a variety of disorders, including cancer. Deregulation of distinct NRs in lung cancer has been associated with numerous events, including mutations, epigenetic modifications, and different signaling cascades. Substantial efforts have been made to develop several small molecules as agonists or antagonists directed to target specific NRs for inhibiting tumor cell growth, migration, and invasion and inducing apoptosis in lung cancer, which makes NRs promising candidates for reliable lung cancer therapeutics. The current work focuses on the importance of various NRs in the development and progression of lung cancer and highlights the different small molecules (e.g., agonist or antagonist) that influence NR expression, with the goal of establishing them as viable therapeutics to combat lung cancer.

Evaluation of expression of vitamin D receptor related lncRNAs in lung cancer

Lung cancer as the most common cancer in the world is associated with high rate of mortality. Previous studies have detected expression of vitamin D receptor (VDR) in lung cancer tissues and reported significant of this gene in determination of patients' survival. Methods: In the current study, we assessed expression of VDR and five long non-coding RNAs (lncRNAs) which have been associated with VDR (MALAT1, SNHG16, SNHG6, LINC00346, LINC00511) in 32 pairs of lung cancer tissues and adjacent non-cancerous tissues (ANCTs) using real time PCR method. Expression of VDR was significantly decreased in tumor tissues obtained from male patients compared with their matched ANCTs (ER = 0.31, P value = 0.02). However, this pattern was not detected in female subjects (ER = 0.93, P value = 0.94). Expression of LINC00346 was significantly decreased in tumoral tissues compared with ANCTs (Expression ratio (ER) = 0.38, P value = 0.03). When evaluating expression of this lncRNA based on the sex of patients, differences in its expression was only significant among males (ER = 0.3, P value = 0.04). VDR expression was significantly associated with sex of patients in a way that most male patients exhibited down-regulation of this gene in their tumor tissue samples compared with the paired ANCTs (P = 0.03). Expression levels of LINC00346 could discriminate lung cancer tissues from ANCTs with sensitivity of 83.3% and specificity of 52.4%. Correlations between expressions of SNHG6 and other genes were all significant in tumoral tissues but insignificant in ANCTs. The current investigation potentiates VDR and LINC00346 as possible participants in the pathogenesis of lung cancer.

Serum 25-hydroxyvitamin D concentrations and lung cancer risk in never-smoking postmenopausal women

PURPOSE

Vitamin D has been implicated in lowering lung cancer risk, but serological data on the association among never-smoking women are limited. We report results examining the association of serum 25-hydroxyvitamin D [25(OH)D] concentrations with lung cancer risk among female never smokers. We also examined whether the association was modified by vitamin D supplementation and serum vitamin A concentrations.

METHODS

In the Women's Health Initiative, including the calcium/vitamin D (CaD) Trial, we selected 298 incident cases [191 non-small cell lung cancer (NSCLC) including 170 adenocarcinoma] and 298 matched controls of never smokers. Baseline serum 25(OH)D was assayed by a chemiluminescent method. Logistic regression was used to estimate odds ratios (ORs) for quartiles and predefined clinical cutoffs of serum 25(OH)D concentrations.

RESULTS

Comparing quartiles 4 versus 1 of serum 25(OH)D concentrations, ORs were 1.06 [95% confidence interval (CI) 0.61-1.84] for all lung cancer, 0.94 (95% CI 0.52-1.69) for NSCLC, and 0.91 (95% CI 0.49-1.68) for adenocarcinoma. Comparing serum 25(OH)D ≥ 75 (high) versus <30 nmol/L (deficient), ORs were 0.76 (95% CI 0.31-1.84) for all lung cancer, 0.71 (95% CI 0.27-1.86) for NSCLC, and 0.81 (95% CI 0.31-2.14) for adenocarcinoma. There is suggestive evidence that CaD supplementation (1 g calcium + 400 IU D₃/day) and a high level of circulating vitamin A may modify the associations of 25(OH)D with lung cancer overall and subtypes (p interaction <0.10).

CONCLUSIONS

In this group of never-smoking postmenopausal women, the results did not support the hypothesis of an association between serum 25(OH)D and lung cancer risk.

Season of diagnosis and survival of advanced lung cancer cases--any correlation?

INTRODUCTION

The influence of season at diagnosis on cancer survival has been an intriguing issue for many years. Most studies have shown a possible correlation in between the seasonality and some cancer type survival. With short expected survival, lung cancer is an arena that still is in need of new prognostic factors and models. We aimed to investigate the effect of season of diagnosis on 3 months, 1 and 2 years survival rates and overall survival of non small cell lung cancer patients.

MATERIALS AND METHODS

The files of non small cell lung cancer patients that were stages IIIB and IV at diagnosis were reviewed retrospectively. According to diagnosis date, the patients were grouped into 4 season groups, autumn, winter, spring and summer.

RESULTS

A total of 279 advanced non small cell lung cancer patients' files were reviewed. Median overall survival was 15 months in the entire population. Overall 3 months, 1 and 2 years survival rates were 91.0%, 58.2% and 31.2% respectively. The season of diagnosis was significantly correlated with 3 months survival rates, being diagnosed in spring being associated with better survival . Also the season was significantly correlated with T stage of the disease. For 1 and 2 years survival rates and overall survival, the season of diagnosis was not significantly correlated. There was no correlation detected between season and overall survivals according to histological subtypes of non small cell lung cancer.

CONCLUSION

As a new finding in advanced non small cell lung cancer patients, it can be concluded that being diagnosed in spring can be a favorable prognostic factor for short term survival.

Characterization of vitamin D receptor (VDR) in lung adenocarcinoma

PURPOSE

The anti-proliferative effects of 1α,25-dihydroxyvitamin D(3) (1,25-D(3), calcitriol, the active form of vitamin D) are mediated by the nuclear vitamin D receptor (VDR). In the present study, we characterized VDR expression in lung adenocarcinoma (AC).

EXPERIMENTAL DESIGN

We examined VDR mRNA expression using a quantitative real-time PCR (qRT-PCR) in 100 patients who underwent surgery for lung AC. In a subset of these patients (n=89), we examined VDR protein expression using immunohistochemistry. We also examined the association of VDR protein expression with circulating serum levels of 25-hydroxyvitamin D(3) (25-D(3)) and 1,25-D(3). The antiproliferative effects and cell cycle arrest of 1,25-D(3) were examined using lung cancer cell lines with high (SKLU-1) as well as low (A549) expression of VDR mRNA.

RESULTS

Higher VDR expression correlates with longer survival after adjusting for age, sex, disease stage and tumor grade (HR 0.73, 95% CI 0.58-0.91). In addition, there was a positive correlation (r=0.38) between serum 1,25-D(3) and tumor VDR protein expression. A greater anti-proliferative effect of 1,25-D(3) was observed in high compared to low VDR-expressing cell lines; these effects corresponded to G1 cell cycle arrest; this was associated with a decline in cyclin D1, S-phase kinase protein 2 (Skp2), retinoblastoma (Rb) and minichromosome maintenance 2 (MCM2) proteins involved in S-phase entry.

CONCLUSIONS

Increased VDR expression in lung AC is associated with improved survival. This may relate to a lower proliferative status and G1 arrest in high VDR-expressing tumors.

Nuclear vitamin D receptor expression is associated with improved survival in non-small cell lung cancer

Vitamin D has been shown to have anti-proliferative effects in a wide variety of cancers including lung cancer. The anticancer effects of vitamin D are mediated primarily by its active metabolite, 1,25-dihydroxyvitamin D (calcitriol), through vitamin D receptor (VDR) signaling. However, thus far there have been no studies evaluating the association between VDR expression and survival outcome in lung cancer. Using immunohistochemical analysis, we evaluated VDR expression, separately in the nucleus and cytoplasm, in lung cancer samples from 73 non-small cell lung carcinoma (NSCLC) patients with no prior therapy, and investigated the association between VDR expression and overall survival (OS). Cox proportional hazard models were used for our primary analyses. There were 44 deaths during a median follow-up of 51 months (range 13-93 months). High nuclear VDR expression was associated with improved OS after adjusting for age, gender, stage, smoking status, and histology (adjusted hazard ratio, 0.36; 95% confidence interval, 0.17-0.79). There was no association between cytoplasmic VDR expression and OS. Our results suggest that nuclear VDR status may be a prognostic marker in NSCLC. Future large studies to replicate our findings and to assess the impact of VDR gene polymorphisms on VDR expression are required as therapies targeting the vitamin D signaling pathway may be influenced by VDR status in the target lung cancer tissue.

Vitamin D receptor expression in normal, premalignant, and malignant human lung tissue

BACKGROUND

There is a strong interest in identifying chemopreventive agents that might help decrease the burden of lung cancer. The active metabolite of vitamin D, 1,25-dihydroxycholecalciferol (calcitriol), has been shown to have antiproliferative effects in several tumor types, mediated by the vitamin D receptor (VDR). This is the first comprehensive survey of VDR expression in a series of human lung tissues, including normal and premalignant central airway biopsies and lung tumors.

METHODS

Immunohistochemical expression of nuclear and cytoplasmic VDR was examined in 180 premalignant or malignant bronchial biopsies from bronchoscopy of 78 high-risk individuals at the Roswell Park Cancer Institute and also in 63 tumor samples from 35 lung cancer patients from the University of Chicago Hospitals. Associations between clinicopathologic data and VDR expression were examined.

RESULTS

VDR expression was present in many samples. In biopsies, VDR was commonly detected throughout the full epithelial layer. Most histologically normal (60%, 53 of 88) and metaplastic (61%, 39 of 64) samples had moderate to high nuclear intensity; dysplastic samples mostly had low nuclear intensity (10 of 18, 55%). In tumor samples, 62% (38 of 61) were lacking cytoplasmic VDR, with nuclear expression present in 79%(49 of 62). Analysis of all samples revealed a positive linear trend between proportion of samples with greater nuclear than cytoplasmic intensity and increasing histologic grade (P < 0.01).

CONCLUSIONS

VDR expression spanned the lung carcinogenesis spectrum. Nuclear expression was similar across various histologies, whereas cytoplasmic expression decreased with increasing histologic grade. These results indicate that there is potential for the use of calcitriol as a chemopreventive agent against the development of lung cancer.

Polymorphisms of vitamin D receptor and survival in early-stage non-small cell lung cancer patients

Our previous analysis suggested that surgery season in the summer time and high vitamin D intake are associated with improved survival in early-stage non-small cell lung cancer (NSCLC) patients. Here, we investigated the associations of vitamin D receptor (VDR) polymorphisms of Cdx-2 G>A, FokI C>T, and BsmI C>T with overall survival (OS) and recurrence-free survival (RFS) in 373 early-stage NSCLC patients. The data were analyzed using log-rank test and Cox proportional hazards models. The median follow-up time was 71 months (range, 0.1-140 months), with 186 deaths and 127 recurrences. There was no association between VDR polymorphisms and survival, overall or among adenocarcinoma patients. Among squamous cell carcinoma (SCC) patients, the G/A+A/A genotype group of the Cdx-2 polymorphism was associated with better OS: the 5-year OS rates were 41% [95% confidence interval (95% CI), 28-53] for the G/G and 55% (95% CI, 39-71) for the G/A+A/A genotypes, respectively (P = 0.04, log-rank test), with the adjusted hazard ratio of 0.56 (95% CI, 0.33-0.95) for G/A+A/A versus G/G. For the joint effects of the three polymorphisms, subjects with two or more "protective" alleles have better OS among SCC patients, with the adjusted hazard ratios of 0.20 (95% CI, 0.09-0.48), 0.40 (95% CI, 0.19-0.87), and 0.43 (95% CI, 0.19-0.97), respectively, for subjects with two, three, and four or more "protective" alleles when compared with subjects with zero or one "protective" allele (P(trend) = 0.71). Similar associations were found in haplotype analysis and for RFS among SCC patients. In conclusion, VDR polymorphisms may be associated with improved survival among SCC patients of early-stage NSCLC.

Cancer survival is dependent on season of diagnosis and sunlight exposure

Sunlight is essential for the production of vitamin D in the body. Evidence exists to suggest that vitamin D metabolites may have a role in tumor growth suppression. In this large study, involving over a million cancer patients from the United Kingdom, we have analyzed the role of season of diagnosis and sunlight exposure in cancer survival for cancers of the breast, colorectum, lung, prostate and at all sites combined. We used population-based data from the Thames Cancer Registry to analyze cancer survival in periods 0-1 and 0-5 years after diagnosis. The analysis was performed using Cox proportional regression analysis adjusting for age and period at diagnosis and including season of diagnosis and sunlight exposure in the preceding months as factors in the analysis. We found evidence of substantial seasonality in cancer survival, with diagnosis in summer and autumn associated with improved survival compared with that in winter, especially in female breast cancer patients and both male and female lung cancer patients (hazard ratios 0.86 [95% CI 0.83-0.89], 0.95 [95% CI 0.92-0.97] and 0.95 [95% CI 0.93-0.98] respectively). Cumulative sunlight exposure in the months preceding diagnosis was also a predictor of subsequent survival, although season of diagnosis was a stronger predictor than cumulative sunlight exposure. We found seasonality in cancer survival to be stronger in women than in men. Our results add to a growing body of evidence that vitamin D metabolites play an important role in cancer survival.