Fluorescence Analysis of Vitamin D Receptor Status of Circulating Tumor Cells (CTCS) in Breast Cancer: From Cell Models to Metastatic Patients

Abstract

The Vitamin D receptor (VDR) expressed in normal breast tissue and breast tumors has been suggested as a new prognostic biomarker in breast cancer (BC). Besides, increasing evidence supports the view that the detection of circulating tumor cells (CTCs) predicts outcome in early and metastatic BC. Consequently, an evaluation of VDR expression in the CTCs of BC patients may allow optimization of their treatment. As an attempt to profile and subtype the CTCs of metastatic patients, we established an innovative fluorescence technique using nine BC cell lines to visualize, define, and compare their individual VDR status. Afterwards, we tested the CTC presence and VDR expression in blood samples (cytospins) collected from 23 metastatic BC patients. The results demonstrated major differences in the VDR levels among the nine cell lines, and VDR positive CTCs were detected in 46% of CTC-positive patients, with a total of 42 CTCs individually analyzed. Due to the limited number of patients in this study, no correlation between VDR expression and BC subtype classification (according to estrogen receptor (ER), progesterone receptor (PR) and HER2) could be determined, but our data support the view that VDR evaluation is a potential new prognostic biomarker to help in the optimization of therapy management for BC patients.

Hormone Receptor Expression in Multicentric/Multifocal versus Unifocal Breast Cancer: Especially the VDR Determines the Outcome Related to Focality

“…Vitamin D and the VDR have become a complex story with an evolving landscape, especially in the last few decades [4,5,9,12,18,19,44,45,46,47,48]. Deuster et al reviewed the importance of Vitamin D and its receptor in the pathogenesis of certain types of cancer such as colorectal, lung but mainly gynecological cancers, where they found the VDR to be upregulated, indicating its relevance for cancer etiology [46].…”

“…Thus, these regimes are currently, according to National Comprehensive Cancer Network (NCCN) guidelines, an indispensable part of the adjuvant therapy for women with hormone receptor-positive (HR+) BC [2,3]. Clinical studies have confirmed that a high HR expression, such as estrogen receptor (ER), progesterone receptor (PR), and vitamin D receptor (VDR), increases the course of the disease [4,5,6,7,8]. In this study, we decided to further investigate the above-mentioned HR expressions, all being nuclear receptors, activated by their steroid hormones and being important targets for both prevention and treatment of BC.…”

“…In BC, VDR expression is inversely associated with a higher cancer incidence, disease progression, and worse prognosis [5,13]. In any case, only the ER, PR, and HER2 status are currently considered as important predictive and prognostic immunohistochemical markers in the therapy decision-making [4,5,14]. For the prophylaxis of the cancer therapy’s side effects, a vitamin D supplementation with a dose between 800 and 1000 IU/d is common [15].…”

Divergent Effect of Tacalcitol (PRI-2191) on Th17 Cells in 4T1 Tumor Bearing Young and Old Ovariectomized Mice

“…Vitamin D deficiency and the low tumor expression level of VDR are correlated with aggressive breast cancer characteristic [18][19][20]. Also preliminary analysis of breast cancer circulating tumor cells suggests VDR as a potential prognostic biomarker [21]. The data showing promotion of tumor growth and metastasis via vitamin D deficiency are presented also using xenografts of human breast cancer cell lines [22] and allografted mouse tumors [23][24][25].…”

Cytoplasmic LXR expression is an independent marker of poor prognosis for patients with early stage primary breast cancer

“…Beside ER and PR, other nuclear receptors (NR) play a role in BC, as we and other have reported earlier (Bock et al 2014;Ditsch et al 2012;Doan et al 2017;Heublein et al 2017;Jalaguier et al 2017;Jeschke et al 2019;Shao et al 2020aShao et al , 2020bZhang et al 2017). Liver X receptors (LXRs) belong to the NR superfamily (Wang and Tontonoz 2018) and have two isotypes, LXRα and LXRβ (encoded by the NR1H3 and NR1H2 gene, respectively).…”