MART-10 represses cholangiocarcinoma cell growth and high vitamin D receptor expression indicates better prognosis for cholangiocarcinoma

Hepatic Nuclear Receptors in Cholestasis-to-Cholangiocarcinoma Pathology

Cholestasis, characterized by impaired bile flow, is associated with an increased risk of cholangiocarcinoma (CCA), a malignancy originating from the biliary epithelium and hepatocytes. Hepatic nuclear receptors (NRs) are pivotal in regulating bile acid and metabolic homeostasis, and their dysregulation is implicated in cholestatic liver diseases and the progression of liver cancer. This review elucidates the role of various hepatic NRs in the pathogenesis of cholestasis-to-CCA progression. It explores their impact on bile acid metabolism as well as their interactions with other signaling pathways implicated in CCA development. Additionally, it introduces available murine models of cholestasis/primary sclerosing cholangitis leading to CCA and discusses the clinical potential of targeting hepatic NRs as a promising approach for the prevention and treatment of cholestatic liver diseases and CCA. Understanding the complex interplay between hepatic NRs and cholestasis-to-CCA pathology holds promise for the development of novel preventive and therapeutic strategies for this devastating disease.

Synthetic Studies on Vitamin D Derivatives with Diverse but Selective Biological Activities

2α-Functionalization of 1α,25-dihydroxyvitamin D3 (active vitamin D3) A-ring enhances binding affinity for the vitamin D receptor (VDR) and prolongs the half-life in target cells due to gaining resistance to CYP24A1-dependant metabolism. The wide variety of modified A-ring precursor enynes for Trost coupling with CD-ring bromoolefin were synthesized from d-glucose. The A-ring modification provided potent, selective biological activities without calcemic side-effects in vivo; for example, 2α-(3-hydroxypropyl)-19-nor-1α,25-dihydroxyvitamin D3 (MART-10) exhibits potent antitumor activity (0.3µg/kg/d, twice/week for 3 weeks) in nude mice inoculated with BxpC-3 cancer cells, 2α-[2-(tetrazol-2-yl)ethyl]-1α,25-dihydroxyvitamin D3 (AH-1) shows better bone-forming effects (0.02µg/kg/d, 5d/week for 4 weeks) in ovariectomized (OVX) rats as an osteoporosis model than natural active vitamin D3, and NS-74c exhibits potent VDR-antagonistic activity (IC50 7.4pM) in HL-60 culture cells. The A-ring modification was also applicable to the synthesis of stable 14-epi-19-nortachysterols, and their novel VDR binding mode was confirmed by X-ray co-crystallographic analysis. 25-Hydroxyvitamin D3 has two independent target molecules: VDR and a sterol regulatory element-binding protein (SREBP)/SREBP cleavage-activating protein (SCAP) complex, and 25-hydroxyvitamin D3 shows SREBP/SCAP inhibitory activity. The VDR-silent vitamin D analog KK-052 with selective SREBP/SCAP inhibitory activity in vivo was developed. A chemical library of side-chain fluorinated vitamin D analogs is currently under construction, and some analogs have shown potent anti-inflammatory activity and therapeutic effects on psoriasis model mice.

The Constellation of Risk Factors and Paraneoplastic Syndromes in Cholangiocarcinoma: Integrating the Endocrine Panel Amid Tumour-Related Biology (A Narrative Review)

Cholangiocarcinomas (CCAs), a heterogeneous group of challenging malignant tumours which originate from the biliary epithelium, are associated with an alarming increasing incidence during recent decades that varies between different regions of the globe. Thus, awareness represents the key operating factor. Our purpose was to overview the field of CCAs following a double perspective: the constellation of the risk factors, and the presence of the paraneoplastic syndromes, emphasizing the endocrine features amid the entire multidisciplinary panel. This is a narrative review. A PubMed-based search of English-language original articles offered the basis of this comprehensive approach. Multiple risk factors underlying different levels of statistical evidence have been listed such as chronic biliary diseases and liver conditions, inflammatory bowel disease, parasitic infections (e.g., Opisthorchis viverrini, Clonorchis sinensis), lifestyle influence (e.g., alcohol, smoking), environmental exposure (e.g., thorotrast, asbestos), and certain genetic and epigenetic interplays. With regard to the endocrine panel, a heterogeneous spectrum should be taken into consideration: non-alcoholic fatty liver disease, obesity, type 2 diabetes mellitus, and potential connections with vitamin D status, glucagon-like peptide 1 receptor, or the galanin system, respectively, with exposure to sex hormone therapy. Amid the numerous dermatologic, hematologic, renal, and neurologic paraneoplastic manifestations in CCAs, the endocrine panel is less described. Humoral hypercalcaemia of malignancy stands as the most frequent humoral paraneoplastic syndrome in CCAs, despite being exceptional when compared to other paraneoplastic (non-endocrine) manifestations and to its reported frequency in other (non-CCAs) cancers (it accompanies 20-30% of all cancers). It represents a poor prognosis marker in CCA; it may be episodic once the tumour relapses. In addition to the therapy that targets the originating malignancy, hypercalcaemia requires the administration of bisphosphonates (e.g., intravenous zoledronic acid) or denosumab. Early detection firstly helps the general wellbeing of a patient due to a prompt medical control of high serum calcium and it also provides a fine biomarker of disease status in selected cases that harbour the capacity of PTHrP secretion. The exact molecular biology and genetic configuration of CCAs that display such endocrine traits is still an open matter, but humoral hypercalcaemia adds to the overall disease burden.

The role of vitamin D3 in follicle development

Vitamin D3 plays a crucial role in female reproduction. As research progresses, the mechanisms of action of vitamin D3 on follicular development have been widely discussed. Firstly, key enzymes involved in the synthesis and metabolism of vitamin D3 have been discovered in the ovary, suggesting that vitamin D3 can be synthesized and metabolized locally within the ovary. Additionally, the detection of vitamin D3 receptors (VDR) in follicles suggests that vitamin D3 may exert its effects by binding specifically to these receptors during follicular development. Further research indicates that vitamin D3 promotes follicular growth by enhancing the development of granulosa cells (GCs) and oocytes. Currently, the mechanism of action of vitamin D3 in follicular development is becoming increasingly clear. Vitamin D3 promotes oocyte development by regulating molecules involved in meiotic arrest in oocytes. It also enhances granulosa cell proliferation by stimulating steroid hormone synthesis and cell cycle regulation. Additionally, vitamin D3 exerts anti-inflammatory effects by reducing oxidative stress and advanced glycation end-products (AGEs), mitigating the detrimental effects of inflammation on follicular development. These functions of vitamin D3 have clinical applications, such as in treating polycystic ovary syndrome (PCOS), improving female fertility, and enhancing outcomes in in vitro fertilization (IVF). This review summarizes the research progress on the role and mechanisms of vitamin D3 in follicular development and briefly summarizes its clinical applications.

VDR is a potential prognostic biomarker and positively correlated with immune infiltration: a comprehensive pan-cancer analysis with experimental verification

The vitamin D receptor (VDR) is a transcription factor that mediates a variety of biological functions of 1,25-dihydroxyvitamin D3. Although there is growing evidence of cytological and animal studies supporting the suppressive role of VDR in cancers, the conclusion is still controversial in human cancers and no systematic pan-cancer analysis of VDR is available. We explored the relationships between VDR expression and prognosis, immune infiltration, tumor microenvironment, or gene set enrichment analysis (GSEA) in 33 types of human cancers based on multiple public databases and R software. Meanwhile, the expression and role of VDR were experimentally validated in papillary thyroid cancer (PTC). VDR expression decreased in 8 types and increased in 12 types of cancer compared with normal tissues. Increased expression of VDR was associated with either good or poor prognosis in 13 cancer types. VDR expression was positively correlated with the infiltration of cancer-associated fibroblasts, macrophages, or neutrophils in 20, 12, and 10 cancer types respectively and this correlation was experimentally validated in PTC. Increased VDR expression was associated with increased percentage of stromal or immune components in tumor microenvironment (TME) in 24 cancer types. VDR positively and negatively correlated genes were enriched in immune cell function and energy metabolism pathways, respectively, in the top 9 highly lethal tumors. Additionally, VDR expression was increased in PTC and inhibited cell proliferation and migration. In conclusion, VDR is a potential prognostic biomarker and positively correlated with immune infiltration as well as stromal or immune components in TME in multiple human cancers.

Prognostic role of vitamin D receptor in digestive system tumours: A systematic review and preliminary meta-analysis

The prognostic value of vitamin D receptor (VDR) in a variety of digestive system tumours remains controversial. In view of this, we conducted a meta-analysis. Published studies (as of Mar 30, 2023) assessing the prognostic role of VDR in digestive system tumours were retrieved. Pooled analyses were conducted based on the hazard ratios (HRs) of high VDR expression extracted from the included studies. If heterogeneity was detected, the random-effects model was used; otherwise, the fixed-effects model was used. Subgroup analysis, sensitivity analysis and meta-regression were performed to explore the sources of heterogeneity. Eight studies with 3,109 patients were included. The pooled results indicated that patients with high VDR expression generally had better overall survival (OS) (pooled HR = 0.67; 95% CI = 0.53-0.85; P = 0.001). Subgroup analyses showed that tumour type was the variable affecting the association between VDR expression and OS. VDR expression in colorectal cancer was not associated with OS (pooled HR = 0.84; 95% CI = 0.68-1.03; P = 0.086). We eliminated publication bias using the "trim and fill" method and found that high VDR expression remained an indicator of good OS (P = 0.001). Only a few studies explored the relationship between VDR expression and cancer-specific survival (CSS) or progression-free survival (PFS), and the pooled results indicated no association between them (P>0.05). VDR expression is a prognostic indicator in digestive system tumours and may also be used as a reference for vitamin D supplementation. Detection of VDR expression not only helps to evaluate prognosis but also to formulate more precise treatment plans for patients with digestive system tumours.

Vitamin D in liver cancer: novel insights and future perspectives

Vitamin D has been a focus of attention in liver cancer due to its direct and indirect antineoplastic effects. This review critically evaluates data from recently published basic and clinical studies investigating the role of vitamin D in liver cancer. Basic studies indicate that vitamin D plays an important role in liver cancer development by suppressing the activity of hepatic stellate cells and Kupffer cells. Furthermore, vitamin D has a direct anti-proliferative, anti-angiogenic, proapoptotic, and prodifferentiative effect on liver cancer cells. Recent investigation suggested several interesting mechanisms of these actions, such as inactivation of Notch signaling, p27 accumulation, and tyrosine-protein kinase Met/extracellular signal-regulated kinases inhibition. On the other hand, data from clinical observational studies, although promising, are still inconclusive. Unfortunately, studies on the effect of vitamin D supplementation were generally focused on short-term outcomes of chronic liver diseases (liver enzyme levels or elastographic finding); therefore, there are still no reliable data on the effect of vitamin D supplementation on liver cancer occurrence or survival.

Effects of Metformin and Vitamin D on Clinical Outcome in Cholangiocarcinoma Patients

BACKGROUND AND AIMS

In the last few years, there has been increasing interest in non-cancer medications and their potential anti-cancer activity. Data are not available in cholangiocarcinoma (CCA) patients. The aim of this study is to fill this gap by investigating the potential impact in terms of clinical outcome of the common non-cancer medications.

METHODS

All consecutive patients with CCAs were retrospectively identified from 7 Italian medical institutions. We investigated the role of intake of vitamin D, aspirin, metformin, statins, and diuretics.

RESULTS

A total of 537 patients with CCAs were identified; 197 patients undergoing surgery were evaluated for disease-free survival (DFS), and 509 patients with an advanced stage were evaluated for overall survival (OS). A longer DFS was found in patients with intake of vitamin D versus never users (HR 0.55, 95% CI 0.32-0.92, p = 0.02). In an advanced stage an association with OS was found in patients with intake of metformin versus never users (HR 0.70, 95% CI 0.52-0.93, p = 0.0162), and in patients who have started taking metformin after chemotherapy versus before chemotherapy and never users (HR 0.44, 95% CI 0.26-0.73, p = 0.0016).

CONCLUSIONS

Our results highlighted that vitamin D intake improves DFS in patients undergoing surgery. Metformin intake after starting chemotherapy can improve the clinical outcome in advanced disease. These results could open up new therapeutic strategies in cholangiocarcinoma patients. We are planning to undertake a prospective study to validate these data.

Decreased vitamin D receptor protein expression is associated with progression and poor prognosis of colorectal cancer patients

This study aimed to investigate vitamin D receptor (VDR) expression levels and evaluate their clinical significance in patients with colorectal cancer (CRC). VDR protein expression was validated by immunohistochemistry in 188 CRC tissues and 134 normal colorectal tissues. The associations between VDR expression and clinicopathologic characteristics, including prognostic outcomes, were analyzed. VDR expression in normal colorectal tissue was higher than that in CRC (83.6% versus 34.6%, P = 4.489 × 10^-20) and generated moderate diagnostic performance for CRC detection (AUC = 0.88, sensitivity = 0.87, specificity = 0.84). Low VDR expression was associated with invasion depth (P = 0.001) and poor survival in CRC (P = 0.031). Univariate Cox analysis demonstrated VDR expression (P = 0.036) was a significant prognostic predictor for survival in patients with CRC. Low VDR expression could be a valuable diagnostic and prognostic biomarker for CRC patients. Targeting VDR may offer a potential therapeutic strategy for blocking CRC.

Metabolism of 2α-[2-(tetrazol-2-yl)ethyl]-1α,25-dihydroxyvitamin D3 by CYP24A1 and biological activity of its 24R-hydroxylated metabolite

Our previous study revealed that the 2α-substituted vitamin D analog 2α-[2-(tetrazol-2-yl)ethyl]-1α,25(OH)₂D₃ (AH-1) exhibited a higher osteocalcin promoter transactivation activity in human osteosarcoma cells and a greater effect on bone mineral density in a rat model of osteoporosis than 1α,25(OH)₂D₃　without increasing blood calcium concentration. Thus, we hypothesized that AH-1 could be a promising therapeutic agent for osteoporosis without any serious side effects. In this study, we compared the CYP24A1-dependent metabolism of AH-1 with that of 1α,25(OH)₂D₃. The resistance to CYP24A1-dependent metabolism could be an important property of vitamin D analogs in prolonging their biological effects. A kinetic analysis was performed using a membrane fraction prepared from recombinant E. coli expressing human CYP24A1. The k_cat/K_m (μM^-1 min^-1) value for AH-1 was 31% of that for 1α,25(OH)₂D₃, suggesting that AH-1 is not as resistant to CYP24A1-dependent metabolism as the other C2-substituted vitamin D analogs such as eldecalcitol [2β-hydroxypropoxy-1α,25(OH)₂D₃]. The major metabolite of AH-1 was the 24R-hydroxylated metabolite, which had high vitamin D receptor (VDR) binding affinity and high HL-60 cell differentiation activity similar to AH-1 itself. In contrast, 1α,25(OH)₂D₃ was metabolized by multistep monooxygenation reactions, which led to the loss of affinity for VDR. Thus, the greater therapeutic effects of AH-1 than those of 1α,25(OH)₂D₃ in in vivo studies using osteoporosis rat models may be due to 24R-hydroxy-AH-1 whose VDR affinity was 91% of that of AH-1.

Apolipoprotein M increases the expression of vitamin D receptor mRNA in colorectal cancer cells detected with duplex fluorescence reverse transcription-quantitative polymerase chain reaction

Apolipoprotein M (ApoM) and the vitamin D receptor (VDR) are apolipoproteins predominantly presenting in high-density lipoprotein (HDL) and a karyophilic protein belonging to the steroid‑thyroid receptor superfamily, respectively. Previous studies have demonstrated that ApoM and VDR are associated with cholesterol metabolism, immune and colorectal cancer regulation. In order to investigate whether ApoM affected the expression of VDR in colorectal cancer cells, a single‑tube duplex fluorescence reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) system was developed to simultaneously detect the mRNA levels of VDR and GAPDH in HT‑29 cells overexpressing ApoM. The results demonstrated that the amplification products were confirmed as the specific fragment of VDR/GAPDH using the DNA sequencing instrument. The sensitivity, linear range, correlation coefficient, amplification efficiency, intra‑assay and inter‑assay coefficients of variation were 40 copies/µl, 4.00x101‑4.00x105 copies/µl, 0.999, 92.42%, 0.09‑0.34% and 0.32‑0.65% for VDR, and 40 copies/µl, 4.00x101‑4.00x105 copies/µl, 0.999, 98.07%, 0.19‑0.43% and 0.40‑0.75% for GAPDH, respectively. The results indicated that the expression of VDR mRNA was significantly higher in HT‑29 cells overexpressing ApoM, compared with the negative control group (P<0.05). In conclusion, the current study successfully developed the single‑tube duplex RT‑qPCR to simultaneously detect VDR and GAPDH expression in colorectal cancer cells. The methodology results demonstrated that the duplex RT‑qPCR system with high sensitivity and specificity could ensure the objectivity and credibility of the detection. The present study confirmed that ApoM significantly increased the expression of VDR in HT‑29 cells. In addition, it was hypothesized that ApoM may be involved in antineoplastic activity via the upregulation of VDR expression, which may provide novel directions for the investigation of ApoM in cancer.