Mechanisms of action of vitamin D in colon cancer

Randomized control trial of moderate dose vitamin D alters microbiota stability and metabolite networks in healthy adults

Evidence indicates that both vitamin D and the gut microbiome are involved in the process of colon carcinogenesis. However, it is unclear what effects supplemental vitamin D3 has on the gut microbiome and its metabolites in healthy adults. We conducted a double-blind, randomized, placebo-controlled trial to identify the acute and long-term microbiota structural and metabolite changes that occur in response to a moderate dose (4,000 IU) of vitamin D3 for 12 weeks in healthy adults. Our results demonstrated a significant increase in serum 25-hydroxy-vitamin D (25(OH)D) in the treatment group compared to placebo (P < 0.0001). Vitamin D3 significantly increased compositional similarity (P < 0.0001) in the treatment group, and enriched members of the Bifidobacteriaceae family. We also identified a significant inverse relationship between the percent change in serum 25(OH)D and microbial stability in the treatment group (R = -0.52, P < 0.019). Furthermore, vitamin D3 supplementation resulted in notable metabolic shifts, in addition to resulting in a drastic rewiring of key gut microbial-metabolic associations. In conclusion, we show that a moderate dose of vitamin D3 among healthy adults has unique acute and persistent effects on the fecal microbiota, and suggest novel mechanisms by which vitamin D may affect the host-microbiota relationship.

IMPORTANCE

Preventative measures to reduce the rise in early-onset colorectal cancer are of critical need. Both vitamin D, dietary and serum levels, and the gut microbiome are implicated in the etiology of colorectal cancer. By understanding the intimate relationship between vitamin D, the gut microbiome, and its metabolites, we may be able to identify key mechanisms that can be targeted for intervention, including inflammation and metabolic dysfunction. Furthermore, the similarity of vitamin D to cholesterol, which is metabolized by the gut microbiome, gives precedence to its ability to produce metabolites that can be further studied and leveraged for controlling colorectal cancer incidence and mortality.

Hypervitaminosis D is correlated with adverse dental implant outcomes: A retrospective case-control study

OBJECTIVES

To investigate vitamin-D levels effect on the survival/success and on marginal bone levels of dental implants.

METHODS

Patients with peri-implant disease and healthy control patients with functionally loaded dental implants were included in this retrospective case-control study. Forty patients with 201 implants were in the diseased-cohort, while thirty-three patients with 90 implants were in the control-cohort. Patient blood 25(OH)D levels were assessed through quantitative blood test. The correlation between abnormal 25(OH)D levels and disease status of each patient was assessed using Fisher's exact tests. The correlation of each implant's outcomes with vitamin-D status was assessed using Kaplan-Meier survival analysis and Mann-Whitney U tests.

RESULTS

Patients with blood 25(OH)D levels >70 ng/mL (hypervitaminosis-D) had a 21.1-fold increase in the risk of implant failure or severe peri-implant bone loss regarding patients with intermediate (>30, ≤70 ng/mL) levels. Kaplan-Meier survival analysis revealed that implants in the hypervitaminosis-D cohort had a survival probability of 73.7 % (95 % CI:56.5-84.5 %) at 19-years after surgery, compared to 95 % for implants in patients with intermediate 25(OH)D levels (95 % CI:88.3-97.9 %). Additionally, implants in the hypervitaminosis-D cohort lost bone faster than implants in the intermediate cohort. These results were specific to the patient cohort with elevated blood 25(OH)D levels and not observed in patients taking vitamin-D supplementation. The impact of hypervitaminosis-D was enriched for implants in the maxilla, and not as apparent for implants in the mandible.

CONCLUSIONS

Blood 25(OH)D levels >70 ng/mL were correlated with adverse implant outcomes, including implant failure and peri-implant bone loss, especially in the maxilla.

CLINICAL RELEVANCE

These results suggest that hypervitaminosis D may be a previously unidentified risk factor for dental implant complications and should be further investigated to elucidate the underlying mechanism.

Associations between diet and nutritional supplements and colorectal cancer: A systematic review

Background and Aim

Colorectal cancer (CRC) is one of the most prevalent cancers around the world. The link between nutrients and the likelihood of developing CRC remains uncertain. The primary objective of the present study was to investigate the potential connection between dietary intake/dietary supplements and the occurrence of CRC through a literature review.

Methods

A comprehensive online search was conducted in PubMed, Scopus, Web of Science, and the Cochrane Library from January 1990 to March 2023 using appropriate keywords. A systematic search was conducted for clinical trials and cohort studies in order to determine the relationship between dietary components/supplements and CRC.

Results

The intake of long-chain n-3 polyunsaturated fatty acids (n-3 LCPUFAs), consisting of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has the potential to decrease the likelihood of developing CRC (eight studies found positive effects and four studies found no association). Some other dietary components such as probiotics, prebiotics, and synbiotics may contribute to suppressing CRC development (three studies found positive effects, whereas three studies did not find any association). There is inconclusive evidence that supplementation with certain micronutrients including vitamin D (one trial found positive effects and another trial reported no association), folate, zinc, and selenium may reduce the risk of CRC.

Conclusion

Some dietary supplements such as n-3 LCPUFAs and probiotics have the potential to reduce the risk of developing CRC. Further studies are necessary to validate these results and understand the underlying mechanisms.

Hsa_circ_0101050 accelerates the progression of Colon cancer by targeting the miR-140-3 p/MELK axis

BACKGROUND

Circular RNAs (circRNAs) are involved in the progression of colon cancer (CC). This study aimed to examine the role of a new circRNA circ_0101050 in CC.

METHODS

Dual-luciferase reporter and RNA immunoprecipitation analyses were performed to validate the target relationships among maternal embryonic leucine zipper kinase (MELK), microRNA (miR)-140-3 p, and circ_0101050. Expression levels were calculated using western blotting and/or quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Western blotting was performed to evaluate the relative expression of Bcl-2 and Bax proteins to determine cell death. Cell Counting Kit-8 (CCK-8) and colony formation assays were performed to determine the proliferative potential of CC cells. The migration rate of CC cells was evaluated using wound healing assays. Tumor formation tests were performed to determine the effect of circ_0101050 on tumor development in vivo.

RESULTS

Elevated levels of circ_0101050 and MELK were observed in CC. By inhibiting circ 0,101,050 or MELK, CC cell proliferation and migration were inhibited, but CC cell apoptosis was promoted. Silencing circ_0101050 also inhibited CC growth in vivo. We also found that miR-140-3 p was downregulated, which alleviated the repressive effects of circ_0101050 knockdown on proliferating and migrating CC cells, as well as the stimulating effect on apoptosis. In addition, the absence of MELK alleviated the effects of miR-140-3 p downregulation, which enhanced CC cell malignancy.

CONCLUSIONS

Circ_0101050 exacerbates malignant phenotypes in CC by targeting the miR-140-3 p/MELK axis. These findings suggested that the circ_0101050/miR-140-3 p/MELK network may be a prospective target for CC treatment.

Determinants of early-onset colorectal cancer: a multicenter case-control study in Iran

BACKGROUND

We aimed to study the risk factors of early-onset colorectal cancer (CRC) incidence in the Iranian population. Early onset CRC in Iran is a relevant health issue that deserves further epidemiological efforts to be defined and controlled as far as possible. Early age screening of low-tract of the intestine would be particularly useful in families of colorectal cancer patients.

METHODS

We analyzed data from a multicenter hospital-based case-control study in Iran (The Iranian Study of Opium and Cancer). Sociodemographic and lifestyle information was collected using validated questionnaires. Multivariate logistic regressions estimated the odds ratios (OR) and 95% confidence intervals (CIs) for the association of early-onset CRC in individuals under the age of 50 and potential risk factors, including physical activity, socioeconomic status, body shape at age 15, dietary factors, vitamin D, cigarettes and waterpipe smoking, opium use and family history of CRC. Additionally, a subgroup analysis was conducted for individuals with a very young age of CRC onset (i.e. <35 years).

RESULTS

We analyzed data of 189 developed CRC below age 50 (99 colon and 90 rectum), and 66 patients under the age 35 (13 colon and 21 rectum). Early CRC was inversely associated with vegetables (OR, 0.59; 95% CI, 0.38-0.92 for 422-576 g/day) and vitamin D (OR, 0.49; 95% CI, 0.26-0.94), and positively associated with red meat intake (OR, 1.80; 1.15-2.83 per 25.65 g/day). Vegetables (OR, 0.51; 95% CI, 0.27-0.98 for 576 g/day), red meat (OR, 2.05; 95% CI, 1.11-3.79 for 25.65 g/day), vitamin D (OR, 0.29; 95% CI, 0.10-0.86) and opium use (OR, 2.61; 95% CI, 1.01-6.74) were associated with early rectum cancer. Results were heterogeneous by cancer site for high fruit and vegetables intakes and cigarette smoking. Family history was associated with CRC (OR, 3.16; 95% CI, 1.29-10.9) and rectum cancer (OR, 3.22; 95% CI, 1.24-14.4) in subjects younger than 35, and, to a lesser extent, with CRC and rectum cancer before age 50.

CONCLUSION

Early-onset CRC was related to the intake of vegetables, vitamin D and red meat in Iran. Early-onset rectum cancer was associated with regular opium use. Family history was associated with early CRC and early rectum cancer, particularly below the age of 35.

Delineating the role of nuclear receptors in colorectal cancer, a focused review

Colorectal cancer (CRC) stands as one of the most prevalent form of cancer globally, causing a significant number of deaths, surpassing 0.9 million in the year 2020. According to GLOBOCAN 2020, CRC ranks third in incidence and second in mortality in both males and females. Despite extensive studies over the years, there is still a need to establish novel therapeutic targets to enhance the patients' survival rate in CRC. Nuclear receptors (NRs) are ligand-activated transcription factors (TFs) that regulate numerous essential biological processes such as differentiation, development, physiology, reproduction, and cellular metabolism. Dysregulation and anomalous expression of different NRs has led to multiple alterations, such as impaired signaling cascades, mutations, and epigenetic changes, leading to various diseases, including cancer. It has been observed that differential expression of various NRs might lead to the initiation and progression of CRC, and are correlated with poor survival outcomes in CRC patients. Despite numerous studies on the mechanism and role of NRs in this cancer, it remains of significant scientific interest primarily due to the diverse functions that various NRs exhibit in regulating key hallmarks of this cancer. Thus, modulating the expression of NRs with their agonists and antagonists, based on their expression levels, holds an immense prospect in the diagnosis, prognosis, and therapeutical modalities of CRC. In this review, we primarily focus on the role and mechanism of NRs in the pathogenesis of CRC and emphasized the significance of targeting these NRs using a variety of agents, which may represent a novel and effective strategy for the prevention and treatment of this cancer.

Vitamin D and cancer

The role of vitamin D in the prevention of chronic diseases including cancer, has received a great deal of attention during the past few decades. The term "Cancer" represents multiple disease states with varying biological complexities. The strongest link between vitamin D and cancer is provided by ecological and studies like observational, in preclinical models. It is apparent that vitamin D exerts diverse biological responses in a tissue specific manner. Moreover, several human factors could affect bioactivity of vitamin D. The mechanism(s) underlying vitamin D initiated anti-carcinogenic effects are diverse and includes changes at the muti-system levels. The oncogenic environment could easily corrupt the traditional role of vitamin D or could ensure resistance to vitamin D mediated responses. Several researchers have identified gaps in our knowledge pertaining to the role of vitamin D in cancer. Further areas are identified to solidify the role of vitamin D in cancer control strategies.

Vitamin D and potential effects on cancers: a review

Cancer is characterized by the abnormal and uncontrollable division and growth of cells that can infiltrate tissues and alter normal physiological function, which will become crucial and life-threatening if left untreated. Cancer can be a result of genetics, such as mutations or environmental causes, including smoking, lack of physical activity, as well as nutritional imbalance in the body. Vitamin D is one of the foremost nutrients that play a crucial role in a variety of biochemical pathways, and it is an important key factor in several diseases. Vitamin D is an essential nutrient for preventing malignancies and a complementary treatment for cancer through direct and indirect biochemical pathways. In this article, we summarized the correlation between vitamin D and various cancers using an extensive search on PubMed, Google Scholar, and Scopus. This paper reviews the role of vitamin D in different types of cancer.

[Calcium, Vitamin D, and Colorectal Cancer]

Colorectal cancer has a high incidence and mortality worldwide, with Westernized lifestyles and diet being significant contributing factors. Vitamin D and calcium have been known to reduce the incidence of colorectal cancer by affecting cell differentiation, proliferation, and apoptosis. Despite observational studies which have suggested that a higher serum vitamin D level can lower the risk of colorectal cancer and improve survival rates, no large-scale randomized controlled trials to establish these benefits have been conducted to date. Calcium intake has also been found to have a beneficial role in reducing the incidence and improving survival rates of colorectal cancer in several observational studies. Moreover, intervention studies have proved its effect in preventing colorectal adenomas. However, there are few intervention studies that have identified the relationship of vitamin D and calcium with colon cancer. To elucidate the impact of vitamin D and calcium supplementation on colorectal cancer, well-designed and large-scale randomized controlled trials are necessary in the future.

Single Nucleotide Polymorphisms in the Vitamin D Metabolic Pathway as Survival Biomarkers in Colorectal Cancer

Several studies have suggested that single nucleotide polymorphisms (SNPs) related to vitamin D metabolism may affect CRC carcinogenesis and survival. The aim of this study was to evaluate the influence of 13 SNPs involved in the vitamin D metabolic pathway on CRC survival. We conducted an observational retrospective cohort study, which included 127 Caucasian CRC patient from the south of Spain. SNPs in VDR, CYP27B1, CYP2R1, CYP24A1, and GC genes were analyzed by real-time polymerase chain reaction. Progression-free survival (PFS) and overall survival (OS) were assessed. Cox regression analysis adjusted for metastasis, age of diagnosis, stage (IIIB, IV or IVB), ECOG score (2-4), lymph node involvement, adjuvant chemotherapy, and no family history of CRC showed that the VDR ApaI (p = 0.036), CYP24A1 rs6068816 (p < 0.001), and GC rs7041 (p = 0.006) were associated with OS in patients diagnosed with CRC, and CYP24A1 rs6068816 (p < 0.001) was associated with PFS adjusted for metastasis, age of diagnosis, stage (IIIB, IV or IVB), ECOG score (2-4), lymph node involvement, adjuvant chemotherapy, and no primary tumor resection. The rest of the SNPs showed no association with CRC survival. Thus, the SNPs mentioned above may have a key role as prognostic biomarkers of CRC.

Vitamin D induces SIRT1 activation through K610 deacetylation in colon cancer

Posttranslational modifications of epigenetic modifiers provide a flexible and timely mechanism for rapid adaptations to the dynamic environment of cancer cells. SIRT1 is an NAD+-dependent epigenetic modifier whose activity is classically associated with healthy aging and longevity, but its function in cancer is not well understood. Here, we reveal that 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3, calcitriol), the active metabolite of vitamin D (VD), promotes SIRT1 activation through auto-deacetylation in human colon carcinoma cells, and identify lysine 610 as an essential driver of SIRT1 activity. Remarkably, our data show that the post-translational control of SIRT1 activity mediates the antiproliferative action of 1,25(OH)2D3. This effect is reproduced by the SIRT1 activator SRT1720, suggesting that SIRT1 activators may offer new therapeutic possibilities for colon cancer patients who are VD deficient or unresponsive. Moreover, this might be extrapolated to inflammation and other VD deficiency-associated and highly prevalent diseases in which SIRT1 plays a prominent role.

Potential tactics with vitamin D and certain phytochemicals for enhancing the effectiveness of immune-checkpoint blockade therapies

Immunotherapy strategies targeting immune checkpoint molecules such as programmed cell death-1 (PD-1) and cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) are revolutionizing oncology. However, its effectiveness is limited in part due to the loss of effector cytotoxic T lymphocytes. Interestingly, supplementation of vitamin D could abolish the repressive effect of programmed cell death-ligand 1 (PD-L1) on CD8⁺ T cells, which might prevent the lymphocytopenia. In addition, vitamin D signaling could contribute to the differentiation of T-regulatory (Treg) cells associated with the expression of Treg markers such as forkhead box P3 (FOXP3) and CTLA-4. Furthermore, vitamin D may be associated with the stimulation of innate immunity. Peroxisome proliferator-activated receptor (PPAR) and estrogen receptor (ESR) signaling, and even the signaling from phosphoinositide-3 kinase (PI3K)/AKT pathway could have inhibitory roles in carcinogenesis possibly via the modulation of immune checkpoint molecules. In some cases, certain small molecules including vitamin D could be a novel therapeutic modality with a promising potential for the better performance of immune checkpoint blockade cancer therapies.

Role of Vitamin D in Head and Neck Cancer-Immune Function, Anti-Tumour Effect, and Its Impact on Patient Prognosis

Head and neck squamous cell carcinoma (HNSCC) describes a heterogeneous group of human neoplasms of the head and neck with high rates of morbidity and mortality, constituting about 3% of all cancers and ~1.5% of all cancer deaths. HNSCC constituted the seventh most prevalent human malignancy and the most common human cancer in the world in 2020, according to multi-population observations conducted by the GLOBOCAN group. Since approximately 60-70% of patients present with stage III/IV neoplastic disease, HNSCC is still one of the leading causes of death in cancer patients worldwide, with an overall survival rate that is too low, not exceeding 40-60% of these patients. Despite the application of newer surgical techniques and the implementation of modern combined oncological treatment, the disease often follows a fatal course due to frequent nodal metastases and local neoplastic recurrences. The role of micronutrients in the initiation, development, and progression of HNSCC has been the subject of considerable research. Of particular interest has been vitamin D, the pleiotropic biologically active fat-soluble family of secosteroids (vitamin-D-like steroids), which constitutes a key regulator of bone, calcium, and phosphate homeostasis, as well as carcinogenesis and the further development of various neoplasms. Considerable evidence suggests that vitamin D plays a key role in cellular proliferation, angiogenesis, immunity, and cellular metabolism. A number of basic science, clinical, and epidemiological studies indicate that vitamin D has multidirectional biological effects and influences anti-cancer intracellular mechanisms and cancer risk, and that vitamin D dietary supplements have various prophylactic benefits. In the 20th century, it was reported that vitamin D may play various roles in the protection and regulation of normal cellular phenotypes and in cancer prevention and adjunctive therapy in various human neoplasms, including HNSCC, by regulating a number of intracellular mechanisms, including control of tumour cell expansion and differentiation, apoptosis, intercellular interactions, angio- and lymphogenesis, immune function, and tumour invasion. These regulatory properties mainly occur indirectly via epigenetic and transcriptional changes regulating the function of transcription factors, chromatin modifiers, non-coding RNA (ncRNAs), and microRNAs (miRs) through protein-protein interactions and signalling pathways. In this way, calcitriol enhances intercellular communication in cancer biology, restores the connection with the extracellular matrix, and promotes the epithelial phenotype; it thus counteracts the tumour-associated detachment from the extracellular matrix and inhibits the formation of metastases. Furthermore, the confirmation that the vitamin D receptor (VDR) is present in many human tissues confirmed the physiopathological significance of vitamin D in various human tumours. Recent studies indicate quantitative associations between exposure to vitamin D and the incidence of HNC, i.e., cancer risk assessment included circulating calcidiol plasma/serum concentrations, vitamin D intake, the presence of the VDR gene polymorphism, and genes involved in the vitamin D metabolism pathway. Moreover, the chemopreventive efficacy of vitamin D in precancerous lesions of the head and neck and their role as predictors of mortality, survival, and recurrence of head and neck cancer are also widely discussed. As such, it may be considered a promising potential anti-cancer agent for developing innovative methods of targeted therapy. The proposed review discusses in detail the mechanisms regulating the relationship between vitamin D and HNSCC. It also provides an overview of the current literature, including key opinion-forming systematic reviews as well as epidemiological, prospective, longitudinal, cross-sectional, and interventional studies based on in vitro and animal models of HNSCC, all of which are accessible via the PubMed/Medline/EMBASE/Cochrane Library databases. This article presents the data in line with increasing clinical credibility.

The effect of 1,25-dihydroxyvitamin D3 on the Wnt signaling pathway in bovine intestinal epithelial cells is mediated by the DKK2 (dickkopf2) Wnt antagonist

The Wnt/β-catenin signaling pathway is aberrantly activated in most colorectal cancers. High-dose 1,25(OH)2D3 has anticancer effect by regulating Wnt signal pathway. However, it is not clear whether high-dose of 1,25(OH)2D3 have an effect on normal cells. The aim of the present study was to investigate the mechanism of high-dose 1,25(OH)2D3 on the Wnt signaling pathway in bovine intestinal epithelial cells. The potential mechanism of action was investigated after knockdown and overexpression of the Wnt pathway inhibitor, DKK2, in intestinal epithelial cells by observing the effects of 1,25(OH)2D3 on proliferation, apoptosis, pluripotency and the expression of genes related to the Wnt/β-catenin signaling pathway. In the present study, we introduced the method of isolation and culture of primary bovine intestinal epithelial cells. After cells were treated with 50ng/mL 1,25(OH)2D3 or DMSO for 48h, total RNA was extracted, and six differentially expressed genes, including SERPINF1, SFRP2, SFRP4, FZD2, WISP1 and DKK2 were identified by transcriptome sequencing, which were related to Wnt signaling pathway. To further explore the mechanism of 1,25(OH)2D3 on the Wnt/β-catenin signaling pathway, we constructed knockdown and overexpression plasmids of DKK2. After transfecting these plasmids into bovine intestinal epithelial cells, we measured the expression of DKK2 mRNA and protein through GFP expression, qRT-PCR and western blot analyses to verify the transfection efficiency. In addition, the CCK-8 assay was used to detect the cell proliferation rate after transfection. Subsequently, the transfected cells were treated with 1,25(OH)2D3 for 48h, and the proliferation- (Ki67 and PCNA), apoptosis- (Bcl-2, p53, casp3 and casp8), pluripotency- (Bmi-1, Lrig1, KRT19 and TUFT1) and Wnt/ β-catenin signaling pathway- related genes (LGR5, DKK2, VDR, β- Catenin, SFRP2, WISP1 and FZD2) were detected by qRT-PCR and western blot analyses. Our results showed that the expression trend of some genes in bovine intestinal epithelial cells under high-dose 1,25(OH)2D3 was consistent with the sequencing results, including SFRP2 (P<0.001), SFRP4 (P<0.05), FZD2 (P<0.01), WISP1 (P<0.001) and DKK2 (P<0.001). In addition, knockdown of DKK2 inhibited cell proliferation (P<0.01), but DKK2 overexpression promoted cell proliferation (P<0.01). Compared to the control group, 1,25(OH)2D3 promoted the expression of Wnt/β-catenin signaling pathway-related proteins in bovine intestinal epithelium, thus maintaining intestinal homeostasis in normal intestinal epithelium. In addition, knockdown and overexpression of DKK2 indicated that 1,25(OH)2D3 weakened the inhibitory effect of DKK2 on the Wnt/β-catenin signaling pathway. Together, these results suggest that high-dose 1,25(OH)2D3 has no killing effect on normal intestinal epithelial cells and regulates Wnt/β-catenin signaling pathway through DKK2.

Vitamin D Promotes Ferroptosis in Colorectal Cancer Stem Cells via SLC7A11 Downregulation

Colorectal cancer stem cells (CCSCs) play important roles in the prognosis, chemoresistance, and treatment failure of colorectal cancer (CRC). Ferroptosis is an effective treatment for CCSCs. Vitamin D (VD) reportedly inhibits colon cancer cell proliferation. However, information on the relationship between VD and ferroptosis in CCSCs is not well documented. In this study, we aimed to understand the effect of VD on ferroptosis in CCSCs. To this end, we treated CCSCs with different concentrations of VD and performed spheroid formation assay and transmission electron microscopy and determined cysteine (Cys), glutathione (GSH), and reactive oxygen species (ROS) levels. Furthermore, functional experiments, western blotting, and qRT-PCR were performed to explore the downstream molecular mechanisms of VD in vitro and in vivo. Results showed that VD treatment significantly inhibited the proliferation of CCSCs and reduced the number of tumour spheroids in vitro. Further evaluations showed that the VD-treated CCSCs exhibited significantly higher ROS levels and lower levels of Cys and GSH as well as thickened mitochondrial membranes. Furthermore, the mitochondria in CCSCs were narrowed and ruptured after VD treatment. These results indicated that VD treatment significantly induced ferroptosis in CCSCs. Further exploration showed that SLC7A11 overexpression significantly attenuated VD-induced ferroptosis in vitro and in vivo. Hence, we concluded that VD induces ferroptosis in CCSCs by downregulating SLC7A11 in vitro and in vivo. These results provide new evidence for the therapeutic use of VD in treating CRC and new insights into VD-induced ferroptosis in CCSCs.

Association of 25-hydroxyvitamin D with risk of overall and colorectal cancer among Japanese using a Mendelian randomization approach

The association between vitamin D and total and colorectal cancer risk was inconsistent in observational studies. We conducted Mendelian randomization approach in which the effect of confounding might be reduced. 110 single nucleotide polymorphisms (SNPs) associated with 25-hydroxyvitamin D concentrations were systematically selected according to the "GWAS Catalog" from all ethnic populations. For the SNP-vitamin D concentration association, 3978 individuals from two Japanese cohorts were included. Regarding SNP-total and colorectal cancer association, 4543 cancer cases and 14,224 controls and 7936 colorectal cancer cases and 38,042 controls, respectively were included from the Japanese Consortium of Genetic Epidemiology and other studies in Japan. There was no significant association between the genetically predicted plasma 25-hydroxyvitamin D concentration and total or colorectal cancer in any of the MR analyses. Odds ratios per doubling in vitamin D concentration were 0.83 (95% confidence interval [CI] 0.63-1.09) for total cancer and 1.00 (95% CI 0.80-1.24) for colorectal cancer in inverse variance weighted method, 0.83 (95% CI 0.57-1.19) for total cancer and 1.01 (95% CI 0.75-1.37) for colorectal cancer in MR-Egger method. Consistent with previous MR analyses among European ancestries, there was no significant association identified between 25-hydroxyvitamin D levels and total or colorectal cancer among Asians.

Association of vitamin D receptor polymorphisms with colorectal cancer susceptibility: A systematic meta-analysis

BACKGROUND

Recent studies have reported an association between vitamin D receptor (VDR) polymorphisms and colorectal cancer (CRC) risk; however, the results are controversial. This meta-analysis was performed to investigate whether the Cdx-2, Tru9I, FokI, BsmI, TaqI, and ApaI polymorphisms were correlated with CRC susceptibility.

METHODS

All potential studies were retrieved by searching the PubMed, EMBASE, and Cochrane Library databases through October 2, 2021. Odds ratios (ORs) with 95% confidence intervals were used to evaluate the correlation between VDR gene Cdx-2, Tru9I, FokI, BsmI, TaqI, and ApaI polymorphisms and CRC risk.

RESULTS

In this meta-analysis, the BsmI variant was significantly correlated with a lower risk of CRC, especially in Caucasian population (B vs b: OR 0.94, 95%CI 0.90-0.99; BB vs bb: OR 0.88; 95%CI 0.79-0.97; BB vs Bb/bb: BB vs Bb/bb: OR 0.89; 95%CI 0.81-0.98). A statistically significant result from the FokI polymorphism was observed in colon cancer rather than rectal cancer (Ff vs FF: OR 0.86, 95%CI 0.84-0.93; ff/Ff vs FF: OR 0.88, 95%CI 0.79-0.98; ff vs Ff/FF: OR 0.90, 95%CI 0.82-0.99). Similarly, Cdx-2 polymorphism was found to be associated with decreased CRC risk among Africans (C vs c: OR 0.50, 95%CI 0.33-0.75; CC vs cc: OR 0.09, 95%CI 0.01-0.77; Cc vs cc: OR 0.49, 95%CI 0.30-0.81; CC/Cc vs cc: OR 0.45, 95%CI 0.28-0.74,).

CONCLUSION

Our findings indicate that VDR polymorphisms are significantly associated with CRC risk.

Fortification by design: A rational approach to designing vitamin D delivery systems for foods and beverages

Over the past few decades, vitamin D deficiency has been recognized as a serious global public health challenge. The World Health Organization has recommended fortification of foods with vitamin D, but this is often challenging because of its low water solubility, poor chemical stability, and low bioavailability. Studies have shown that these challenges can be overcome by encapsulating vitamin D within well-designed delivery systems containing nanoscale or microscale particles. The characteristics of these particles, such as their composition, size, structure, interfacial properties, and charge, can be controlled to attain desired functionality for specific applications. Recently, there has been great interest in the design, production, and application of vitamin-D loaded delivery systems. Many of the delivery systems reported in the literature are unsuitable for widespread application due to the complexity and high costs of the processing operations required to fabricate them, or because they are incompatible with food matrices. In this article, the concept of "fortification by design" is introduced, which involves a systematic approach to the design, production, and testing of colloidal delivery systems for the encapsulation and fortification of oil-soluble vitamins, using vitamin D as a model. Initially, the challenges associated with the incorporation of vitamin D into foods and beverages are reviewed. The fortification by design concept is then described, which involves several steps: (i) selection of appropriate vitamin D form; (ii) selection of appropriate food matrix; (iii) identification of appropriate delivery system; (iv) identification of appropriate production method; (vii) establishment of appropriate testing procedures; and (viii) system optimization.

Nongenomic Activities of Vitamin D

Vitamin D shows a variety of pleiotropic activities which cannot be fully explained by the stimulation of classic pathway- and vitamin D receptor (VDR)-dependent transcriptional modulation. Thus, existence of rapid and nongenomic responses to vitamin D was suggested. An active form of vitamin D (calcitriol, 1,25(OH)₂D₃) is an essential regulator of calcium-phosphate homeostasis, and this process is tightly regulated by VDR genomic activity. However, it seems that early in evolution, the production of secosteroids (vitamin-D-like steroids) and their subsequent photodegradation served as a protective mechanism against ultraviolet radiation and oxidative stress. Consequently, direct cell-protective activities of vitamin D were proven. Furthermore, calcitriol triggers rapid calcium influx through epithelia and its uptake by a variety of cells. Subsequently, protein disulfide-isomerase A3 (PDIA3) was described as a membrane vitamin D receptor responsible for rapid nongenomic responses. Vitamin D was also found to stimulate a release of secondary massagers and modulate several intracellular processes-including cell cycle, proliferation, or immune responses-through wingless (WNT), sonic hedgehog (SSH), STAT1-3, or NF-kappaB pathways. Megalin and its coreceptor, cubilin, facilitate the import of vitamin D complex with vitamin-D-binding protein (DBP), and its involvement in rapid membrane responses was suggested. Vitamin D also directly and indirectly influences mitochondrial function, including fusion-fission, energy production, mitochondrial membrane potential, activity of ion channels, and apoptosis. Although mechanisms of the nongenomic responses to vitamin D are still not fully understood, in this review, their impact on physiology, pathology, and potential clinical applications will be discussed.

Vitamin D in Cancer Prevention: Gaps in Current Knowledge and Room for Hope

Intensive epigenome and transcriptome analyses have unveiled numerous biological mechanisms, including the regulation of cell differentiation, proliferation, and induced apoptosis in neoplastic cells, as well as the modulation of the antineoplastic action of the immune system, which plausibly explains the observed population-based relationship between low vitamin D status and increased cancer risk. However, large randomized clinical trials involving cholecalciferol supplementation have so far failed to show the potential of such interventions in cancer prevention. In this article, we attempt to reconcile the supposed contradiction of these findings by undertaking a thorough review of the literature, including an assessment of the limitations in the design, conduct, and analysis of the studies conducted thus far. We examine the long-standing dilemma of whether the beneficial effects of vitamin D levels increase significantly above a critical threshold or if the conjecture is valid that an increase in available cholecalciferol translates directly into an increase in calcitriol activity. In addition, we try to shed light on the high interindividual epigenetic and transcriptomic variability in response to cholecalciferol supplementation. Moreover, we critically review the standards of interpretation of the available study results and propose criteria that could allow us to reach sound conclusions in this field. Finally, we advocate for options tailored to individual vitamin D needs, combined with a comprehensive intervention that favors prevention through a healthy environment and responsible health behaviors.

Vitamin D and Colorectal Cancer: Current Perspectives and Future Directions

Vitamin D is considered to be the main mediator of the beneficial effects of sun exposure. In humans, highest expression of Vitamin D receptors is found in the intestinal tract. In addition, 1α,25-dihydroxyvitamin D3 (or calcitriol), the most active Vitamin D metabolite, plays important homeostatic roles in the intestine, particularly calcium absorption. Vitamin D deficiency is defined as a serum 25-hydroxyvitamin D [25(OH)D] level of < 20 ng/mL. Previous studies show that higher circulating 25(OH)D levels are associated with reduced risk of colorectal cancer (CRC) and improved survival. Most research to date has been conducted in animals, specifically mice. Although human studies have a limited number of participants, one study recruiting a large cohort of patients with advanced or metastatic CRC revealed that higher plasma 25(OH)D levels are associated with improved overall and progression-free survival. However, the effects of Vitamin D supplementation on incidence and mortality of CRC remain inconclusive. Although Vitamin D may help to prevent cancer, there is a paucity of research demonstrating conclusively that Vitamin D alters prognosis after chemotherapy. Here, we review the mechanisms by which Vitamin D affects CRC, as well as the results of clinical, epidemiological, and human intervention studies. We also discuss current perspectives and future directions regarding Vitamin D and CRC.

The Effect of Vitamin D and Its Analogs in Ovarian Cancer

Ovarian cancer is one of the deadliest cancers in women, due to its heterogeneity and usually late diagnosis. The current first-line therapies of debulking surgery and intensive chemotherapy cause debilitating side effects. Therefore, there is an unmet medical need to find new and effective therapies with fewer side effects, or adjuvant therapies, which could reduce the necessary doses of chemotherapeutics. Vitamin D is one of the main regulators of serum calcium and phosphorus homeostasis, but it has also anticancer effects. It induces differentiation and apoptosis, reduces proliferation and metastatic potential of cancer cells. However, doses that would be effective against cancer cause hypercalcemia. For this reason, synthetic and less calcemic analogs have been developed and tested in terms of their anticancer effect. The anticancer role of vitamin D is best understood in colorectal, breast, and prostate cancer and much less research has been done in ovarian cancer. In this review, we thus summarize the studies on the role of vitamin D and its analogs in vitro and in vivo in ovarian cancer models.

Bioactive Vitamin D Attenuates MED28-Mediated Cell Growth and Epithelial–Mesenchymal Transition in Human Colorectal Cancer Cells

Inadequate vitamin D status may increase the risk of developing multiple types of cancer. Epidemiological studies suggest an inverse association between 25-hydroxyvitamin D₃ (25(OH)D₃) and malignancy, including colorectal cancer. Previous studies have suggested that MED28, a Mediator subunit involved in transcriptional regulation, is associated with the growth of colorectal cancer cells; however, its role in the progression of metastasis such as epithelial–mesenchymal transition (EMT) and cell migration of colorectal cancer is unclear at present. The aim of this study was to investigate a potentially suppressive effect of calcitriol, 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), a bioactive form of vitamin D, and the role of MED28 in the progression of EMT in human colorectal cancer cells. Suppression of MED28 increased the expression of E-cadherin and reduced the expression of several mesenchymal and migration biomarkers and Wnt/β-catenin signaling molecules, whereas overexpression of MED28 enhanced the EMT features. Calcitriol suppressed the expression of MED28, and the effect of calcitriol mirrored that of MED28 silencing. Our data indicate that calcitriol attenuated MED28-mediated cell growth and EMT in human colorectal cancer cells, underlining the significance of MED28 in the progression of colorectal cancer and supporting the potential translational application of calcitriol.

Anti-colorectal cancer effects of seaweed-derived bioactive compounds

Seaweeds are classified as Chlorophyta, Rhodophyta, and Phaeophyta. They constitute a number of the most significant repositories of new therapeutic compounds for human use. Seaweed has been proven to possess diverse bioactive properties, which include anticancer properties. The present review focuses on colorectal cancer, which is a primary cause of cancer-related mortality in humans. In addition, it discusses various compounds derived from a series of seaweeds that have been shown to eradicate or slow the progression of cancer. Therapeutic compounds extracted from seaweed have shown activity against colorectal cancer. Furthermore, the mechanisms through which these compounds can induce apoptosis in vitro and in vivo were reviewed. This review emphasizes the potential utility of seaweeds as anticancer agents through the consideration of the capability of compounds present in seaweeds to fight against colorectal cancer.

Vitamin–Microbiota Crosstalk in Intestinal Inflammation and Carcinogenesis

Inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CAC) are common diseases of the digestive system. Vitamin deficiencies and gut microbiota dysbiosis have a close relationship with the risk, development, and progression of IBD and CAC. There is a strong link between vitamins and the gut microbiome. Vitamins are extremely crucial for maintaining a healthy gut microbiota, promoting growth and development, metabolism, and innate immunity. Gut microbiota can not only influence the transport process of vitamins, but also produce vitamins to compensate for insufficient food intake. Emerging evidence suggests that oral vitamin supplementation can reduce inflammation levels and improve disease prognosis. In addition, improving the diet structure and consuming foods rich in vitamins not only help to improve the vitamin deficiency, but also help to reduce the risk of IBD. Fecal microbiota transplantation (FMT) and the application of vitamin-producing probiotics can better assist in the treatment of intestinal diseases. In this review, we discuss the interaction and therapeutic roles of vitamins and gut microbiota in IBD and CAC. We also summarize the methods of treating IBD and CAC by modulating vitamins. This may highlight strategies to target gut-microbiota-dependent alterations in vitamin metabolism in the context of IBD and CAC therapy.

Genomic analysis of 1,25-dihydroxyvitamin D3 action in mouse intestine reveals compartment and segment-specific gene regulatory effects

1,25-dihydroxyvitamin D (VD) regulates intestinal calcium absorption in the small intestine (SI) and also reduces risk of colonic inflammation and cancer. However, the intestine compartment-specific target genes of VD signaling are unknown. Here, we examined VD action across three functional compartments of the intestine using RNA-seq to measure VD-induced changes in gene expression and Chromatin Immunoprecipitation with next generation sequencing to measure vitamin D receptor (VDR) genomic binding. We found that VD regulated the expression of 55 shared transcripts in the SI crypt, SI villi, and in the colon, including Cyp24a1, S100g, Trpv6, and Slc30a10. Other VD-regulated transcripts were unique to the SI crypt (162 up, 210 down), villi (199 up, 63 down), or colon (102 up, 28 down), but this did not correlate with mRNA levels of the VDR. Furthermore, bioinformatic analysis identified unique VD-regulated biological functions in each compartment. VDR-binding sites were found in 70% of upregulated genes from the colon and SI villi but were less common in upregulated genes from the SI crypt and among downregulated genes, suggesting some transcript-level VD effects are likely indirect. Consistent with this, we show that VD regulated the expression of other transcription factors and their downstream targets. Finally, we demonstrate that compartment-specific VD-mediated gene expression was associated with compartment-specific VDR-binding sites (<30% of targets) and enrichment of intestinal transcription factor-binding motifs within VDR-binding peaks. Taken together, our data reveal unique spatial patterns of VD action in the intestine and suggest novel mechanisms that could account for compartment-specific functions of this hormone.

Low Vitamin D Status is Not Associated with the Aggressive Pathological Features of Papillary Thyroid Cancer

Objectives:

In the present study, we investigated the effects of Vitamin D (vit D) deficiency on aggressiveness of papillary thyroid cancer (PTC).

Methods:

Patients with PTC confirmed with pathological examination, whom were operated by a single surgeon between 2012 and 2017, were included in the study. The data of the patients were analyzed retrospectively. Cancers other than PTC, patients with hyperthyroidism and/or using antithyroid drugs were excluded from the study. The patients were classified as four quartiles according to serum Vit D levels; category 1 (<7.1 ng/mL), category 2 (7.2–11.8 ng/mL), category 3 (11.9–23.4 ng/mL) and category 4 (>23.5 ng/mL).

Results:

A total of 133 patients (103 female, 30 male) with mean age of 46.4±13.6 (17–82) years were included in the study. There was no significant difference between the categories in terms of preoperative Vit D values according to the evaluated tumor aggressiveness characteristics. It was determined that the presence of tumor with a size above 1 cm and T3/4 tumor were not affected by Vit D level. There was no significant difference between Vit D categories regarding the characteristics of aggressiveness such as multicentricity, lymphovascular invasion, central, and lateral metastases.

Conclusion:

According to our results, serum Vit D levels are not associated with the aggressive tumor characteristics of PTC.

Effect of extracts from eggs of Helix aspersa maxima and Helix aspersa aspersa snails on Caco-2 colon cancer cells

Background

Colorectal cancer is the third most commonly diagnosed cancer. Natural compounds, administered together with conventional chemotherapeutic agent(s) and/or radiotherapy, may be a novel element in the combination therapy of this cancer. Considering the anticancer properties of compounds derived from different tissues of various snail species confirmed earlier, the purpose of the present research was to evaluate the effect of extracts from eggs of Helix aspera maxima and Helix aspersa aspersa snails, and fractions of extracts containing particles of different molecular weights on Caco-2 human epithelial colorectal adenocarcinoma cells.

Methods

The extracts and fractions were analyzed for antioxidant activity, phenols and total carbohydrates using colorimetric methods. Lipid peroxidation products and glutathione in eggs were also examined using these methods. Crude protein and fat in eggs were determined. Molecular weights of egg proteins and glycoproteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Astaxanthin, selected vitamins and amino acids in eggs were measured using liquid chromatography methods, and minerals by emission spectroscopy, mass spectrometry or X-ray fluorescence. The action of extracts on the cell viability was determined by the MTT (methylthiazolyldiphenyl-tetrazolium bromide) test, based on the mitochondrial oxidative activity, after 24 and 72 h of treatment. The influence of fractions on the cell viability was assayed after 24 h. The effect of extracts on the percentage of live and dead cells was evaluated by the trypan blue assay, in which live cells exclude trypan blue, while dead cells take up this dye, after 12, 24, 48 and 72 h of treatment. Their influence on the integrity of cell membranes was determined based on the activity of LDH (lactate dehydrogenase), released from damaged cells, after 24 and 72 h of treatment. Then, the effect of extracts on the content of lipid peroxidation products in cells was examined using colorimetric method, after 24 h of treatment. Their influence on types of cell death was determined by flow cytometry, after this time.

Results

The extracts and their fractions containing molecules <3 kDa decreased the cell viability, after 24 h of treatment. The extracts reduced the percentage of live cells (also after 48 h), increased the degree of cell membrane damage and the amount of lipid peroxidation products, induced apoptosis and reduced necrosis.

Conclusions

Antioxidants, phenols, lipid peroxidation products, anticancer peptides, restriction of methionine, appropriate ratio of essential amino acids to non-essential amino acids, vitamin D3, Ca, Mg, S, Cu, Mn, Zn, Se and other bioactive compounds comprised in the extracts and their additive and synergistic effects may have influenced Caco-2 cells. Natural extracts or the chemical compounds contained in them might be used in the combination therapy of colorectal cancer, which requires further research.

Vitamin D and Cancer: An Historical Overview of the Epidemiology and Mechanisms

This is a narrative review of the evidence supporting vitamin D's anticancer actions. The first section reviews the findings from ecological studies of cancer with respect to indices of solar radiation, which found a reduced risk of incidence and mortality for approximately 23 types of cancer. Meta-analyses of observational studies reported the inverse correlations of serum 25-hydroxyvitamin D [25(OH)D] with the incidence of 12 types of cancer. Case-control studies with a 25(OH)D concentration measured near the time of cancer diagnosis are stronger than nested case-control and cohort studies as long follow-up times reduce the correlations due to changes in 25(OH)D with time. There is no evidence that undiagnosed cancer reduces 25(OH)D concentrations unless the cancer is at a very advanced stage. Meta-analyses of cancer incidence with respect to dietary intake have had limited success due to the low amount of vitamin D in most diets. An analysis of 25(OH)D-cancer incidence rates suggests that achieving 80 ng/mL vs. 10 ng/mL would reduce cancer incidence rates by 70 ± 10%. Clinical trials have provided limited support for the UVB-vitamin D-cancer hypothesis due to poor design and execution. In recent decades, many experimental studies in cultured cells and animal models have described a wide range of anticancer effects of vitamin D compounds. This paper will review studies showing the inhibition of tumor cell proliferation, dedifferentiation, and invasion together with the sensitization to proapoptotic agents. Moreover, 1,25-(OH)2D3 and other vitamin D receptor agonists modulate the biology of several types of stromal cells such as fibroblasts, endothelial and immune cells in a way that interferes the apparition of metastases. In sum, the available mechanistic data support the global protective action of vitamin D against several important types of cancer.

A Narrative Review of the Evidence for Variations in Serum 25-Hydroxyvitamin D Concentration Thresholds for Optimal Health

Vitamin D3 has many important health benefits. Unfortunately, these benefits are not widely known among health care personnel and the general public. As a result, most of the world's population has serum 25-hydroxyvitamin D (25(OH)D) concentrations far below optimal values. This narrative review examines the evidence for the major causes of death including cardiovascular disease, hypertension, cancer, type 2 diabetes mellitus, and COVID-19 with regard to sub-optimal 25(OH)D concentrations. Evidence for the beneficial effects comes from a variety of approaches including ecological and observational studies, studies of mechanisms, and Mendelian randomization studies. Although randomized controlled trials (RCTs) are generally considered the strongest form of evidence for pharmaceutical drugs, the study designs and the conduct of RCTs performed for vitamin D have mostly been flawed for the following reasons: they have been based on vitamin D dose rather than on baseline and achieved 25(OH)D concentrations; they have involved participants with 25(OH)D concentrations above the population mean; they have given low vitamin D doses; and they have permitted other sources of vitamin D. Thus, the strongest evidence generally comes from the other types of studies. The general finding is that optimal 25(OH)D concentrations to support health and wellbeing are above 30 ng/mL (75 nmol/L) for cardiovascular disease and all-cause mortality rate, whereas the thresholds for several other outcomes appear to range up to 40 or 50 ng/mL. The most efficient way to achieve these concentrations is through vitamin D supplementation. Although additional studies are warranted, raising serum 25(OH)D concentrations to optimal concentrations will result in a significant reduction in preventable illness and death.

Wnt signaling pathway in cancer immunotherapy

Wnt/β-catenin signaling is a highly conserved pathway that regulates cell proliferation, differentiation, apoptosis, stem cell self-renewal, tissue homeostasis, and wound healing. Dysregulation of the Wnt pathway is intricately involved in almost all stages of tumorigenesis in various cancers. Through direct and/or indirect effects on effector T cells, T-regulatory cells, T-helper cells, dendritic cells, and other cytokine-expressing immune cells, abnormal activation of Wnt/β-catenin signaling benefits immune exclusion and hinders T-cell-mediated antitumor immune responses. Activation of Wnt signaling results in increased resistance to immunotherapies. In this review, we summarize the process by which Wnt signaling affects cancer and immune surveillance, and the potential for targeting the Wnt-signaling pathway via cancer immunotherapy.

Longitudinal Analysis of 1α,25-dihidroxyvitamin D3 and Homocysteine Changes in Colorectal Cancer

Simple Summary

Vitamin D₃ and homocysteine level abnormalities are both strongly related to colorectal cancer (CRC) etiology. The aim of this retrospective study was to investigate the longitudinal change in these two parameters and the relationships between the two, in addition with other clinicopathological and laboratory parameters. A swoosh-shaped trend was observed for the change in serum homocysteine levels of all of the CRC patients. The circulating vitamin D₃ level was constant or increased in those patients without metastasis. After an initial increase, the disease-worsening effect of metastases cancelled out all of the positive effects of vitamin D₃ in metastatic patients, even despite its continuous supplementation. Right-sided tumors, male sex, and the pathological values of serum lipids, albumin, total protein, and inflammatory markers were associated with lower vitamin D₃ and higher homocysteine level. Based on our results, we recommend a modified vitamin D₃ supplementation regimen for metastatic CRC, which includes laboratory measurement-based titration.

Abstract

Background: 1α,25-dihydroxycholecalciferol (1,25(OH)₂D₃) and homocysteine are known to play a role in the pathophysiology of colorectal cancer (CRC). In health, the two changes are inversely proportional to each other, but little is known about their combined effect in CRC. Methods: The serum 1,25(OH)₂D₃ and the homocysteine levels of eighty-six CRC patients were measured, who were enrolled into four cohorts based on the presence of metastases (Adj vs. Met) and vitamin D₃ supplementation (ND vs. D). Results: 1,25(OH)₂D₃ was constant (Adj-ND), increased significantly (Adj-D, p = 0.0261), decreased (Met-ND), or returned close to the baseline after an initial increase (Met-D). The longitudinal increase in 1,25(OH)₂D₃ (HR: 0.9130, p = 0.0111) positively affected the overall survival in non-metastatic CRC, however, this effect was cancelled out in those with metastasis (p = 0.0107). The increase in homocysteine negatively affected both the overall (HR: 1.0940, p = 0.0067) and the progression-free survival (HR: 1.0845, p = 0.0073). Lower 1,25(OH)₂D₃ and/or higher homocysteine level was characteristic for patients with higher serum lipids, albumin, total protein, white blood cell and platelet count, male sex, and right-sided tumors. No statistically justifiable connection was found between the target variables. Conclusions: A measurement-based titration of vitamin D₃ supplementation and better management of comorbidities are recommended for CRC.

Vitamin D and adrenal gland: Myth or reality? A systematic review

In recent years, vitamin D has become the protagonist in many studies. From cardiology to oncology the spotlight was on this vitamin. While in the past it was considered for its important role in phospho-calcium metabolism and skeletal disorders; today by studying it better, thousands of scenarios and facets have opened up on this vitamin which is actually a hormone in all respects. There are authoritative studies that demonstrate its activity in vitro and in vivo on: carcinogenesis, inflammation, autoimmunity and endocrinopathies. Its role has been studied in type 1 and type 2 diabetes mellitus, in Hashimoto or Graves' thyroiditis and even in adrenal gland diseases. In fact, there are several studies that demonstrate the possible correlations between vitamin D and: Addison's disease, Cushing disease, hyperaldosteronism or adrenocortical tumors. Moreover, this fascinating hormone and adrenal gland even seem to be deeply connected by common genetic pathways. This review aimed to analyze the works that have tried to study the possible influence of vitamin D on adrenal diseases. In this review we analyze the works that have tried to study the possible influence of vita-min D on adrenal disease.

Vitamin D: A Critical Regulator of Intestinal Physiology

Calcium is required for the functioning of numerous biological processes and is essential for skeletal health. The major source of new calcium is from the diet. The central role of vitamin D in the maintenance of calcium homeostasis is to increase the absorption of ingested calcium from the intestine. The critical importance of vitamin D in this process is noted in the causal link between vitamin D deficiency and rickets, as well as in studies using genetically modified mice including mice deficient in the vitamin D receptor (Vdr null mice) or in the cytochrome P‐450 enzyme, 25‐hydroxyvitamin D₃‐1α‐ hydroxylase (CYP27B1) that converts 25‐hydroxyvitamin D₃ to the hormonally active form of vitamin D, 1,25‐dihydroxyvitamin D₃ [1,25(OH)₂D₃] (Cyp27b1 null mice). When these mice are fed diets with high calcium and lactose, rickets is prevented. The studies using mouse models provide supporting evidence indicating that the major physiological function of 1,25(OH)₂D₃/VDR is intestinal calcium absorption. This review summarizes what is known about mechanisms involved in vitamin D‐regulated intestinal calcium absorption. Recent studies suggest that vitamin D does not affect a single entity, but that a complex network of calcium‐regulating components is involved in the process of 1,25(OH)₂D₃‐mediated active intestinal calcium absorption. In addition, numerous 1,25(OH)₂D₃ actions in the intestine have been described independent of calcium absorption. Although the translatability to humans requires further definition, an overview is presented that provides compelling evidence from the laboratory of 1,25(OH)₂D₃ intestinal effects, which include the regulation of adhesion molecules to enhance barrier function, the regulation of intestinal stem cell function, cellular homeostasis of other divalent cations, the regulation of drug metabolizing enzymes, and anti‐inflammatory effects. © 2021 The Author. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

VDR Signaling via the Enzyme NAT2 Inhibits Colorectal Cancer Progression

Recent epidemiological and preclinical evidence indicates that vitamin D₃ inhibits colorectal cancer (CRC) progression, but the mechanism has not been completely elucidated. This study was designed to determine the protective effects of vitamin D₃ and identify crucial targets and regulatory mechanisms in CRC. First, we confirmed that 1,25(OH)₂D₃, the active form of vitamin D₃, suppressed the aggressive phenotype of CRC in vitro and in vivo. Based on a network pharmacological analysis, N-acetyltransferase 2 (NAT2) was identified as a potential target of vitamin D₃ against CRC. Clinical data of CRC patients from our hospital and bioinformatics analysis by online databases indicated that NAT2 was downregulated in CRC specimens and that the lower expression of NAT2 was correlated with a higher metastasis risk and lower survival rate of CRC patients. Furthermore, we found that NAT2 suppressed the proliferation and migration capacity of CRC cells, and the JAK1/STAT3 signaling pathway might be the underlying mechanism. Moreover, Western blot and immunofluorescence staining assays demonstrated that 1,25(OH)₂D₃ promoted NAT2 expression, and the chromatin immunoprecipitation assay indicated that the vitamin D receptor (VDR) transcriptionally regulated NAT2. These findings expand the potential uses of vitamin D₃ against CRC and introduce VDR signaling via the enzyme NAT2 as a potential diagnostic and therapeutic target for CRC.

Total Vitamin D Intake and Risks of Early-Onset Colorectal Cancer and Precursors

BACKGROUND & AIMS

Vitamin D has been implicated in colorectal cancer (CRC) pathogenesis, but it remains unknown whether total vitamin D intake is associated with early-onset CRC and precursors diagnosed before age 50.

METHODS

We prospectively examined the association between total vitamin D intake and risks of early-onset CRC and precursors among women enrolled in the Nurses' Health Study II. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for early-onset CRC were estimated with Cox proportional hazards model. Multivariable-adjusted odds ratios (ORs) and 95% CIs for early-onset conventional adenoma and serrated polyp were estimated with logistic regression model.

RESULTS

We documented 111 incident cases of early-onset CRC during 1,250,560 person-years of follow-up (1991 to 2015). Higher total vitamin D intake was significantly associated with a reduced risk of early-onset CRC (HR for ≥450 IU/day vs <300 IU/day, 0.49; 95% CI, 0.26-0.93; P for trend = .01). The HR per 400 IU/day increase was 0.46 (95% CI, 0.26-0.83). The inverse association was significant and appeared more evident for dietary sources of vitamin D (HR per 400 IU/day increase, 0.34; 95% CI, 0.15-0.79) than supplemental vitamin D (HR per 400 IU/day increase, 0.77; 95% CI, 0.37-1.62). For CRC precursors, the ORs per 400 IU/day increase were 0.76 (95% CI, 0.65-0.88) for conventional adenoma (n = 1,439) and 0.85 (95% CI, 0.75-0.97) for serrated polyp (n = 1,878).

CONCLUSIONS

In a cohort of younger women, higher total vitamin D intake was associated with decreased risks of early-onset CRC and precursors.

Vitamin D and the risk for cancer: A molecular analysis

Uncontrolled overgrowth of cells, such as in cancer, is an unavoidable risk in life that affects nearly every second individual in industrialized countries. However, in part this risk can be controlled through lifestyle adjustments, such as the avoidance of smoking, unhealthy diet, obesity, physical inactivity and other cancer risk factors. A low vitaminD status is a risk in particular for cancers of colon, prostate, breast and leukocytes. VitaminD₃ is produced non-enzymatically, when the cholesterol precursor 7-dehydrocholesterol is exposed to UV-B from sunlight, i.e., all cholesterol synthesizing species, including humans, can make vitaminD₃. VitaminD endocrinology started some 550million years ago, when the metabolite 1α,25-dihydroxyvitaminD₃ and the transcription factor vitaminD receptor teamed up for regulating the expression of hundreds of target genes in a multitude of different tissues and cell types. Initially, these genes were focused on the control of energy homeostasis, which later also involved energy-demanding innate and adaptive immunity. Rapidly growing cells of the immune system as well as those of malignant tumors rely on comparable genes and pathways, some of which are modulated by vitaminD. Accordingly, vitaminD has anti-cancer effects both directly via controling the differentiation, proliferation and apoptosis of neoplastic cells as well as indirectly through regulating immune cells that belong to the microenvironment of malignant tumors. This review discusses effects of vitaminD on the epigenome and transcriptome of stromal and tumor cells, inter-individual variations in vitaminD responsiveness and their relation to the prevention and possible therapy of cancer.

Epigenetic Reprogramming of Tumor-Associated Fibroblasts in Lung Cancer: Therapeutic Opportunities

Simple Summary

Lung cancer is the leading cause of cancer death among both men and women, partly due to limited therapy responses. New avenues of knowledge are indicating that lung cancer cells do not form a tumor in isolation but rather obtain essential support from their surrounding host tissue rich in altered fibroblasts. Notably, there is growing evidence that tumor progression and even the current limited responses to therapies could be prevented by rescuing the normal behavior of fibroblasts, which are critical housekeepers of normal tissue function. For this purpose, it is key to improve our understanding of the molecular mechanisms driving the pathologic alterations of fibroblasts in cancer. This work provides a comprehensive review of the main molecular mechanisms involved in fibroblast transformation based on epigenetic reprogramming, and summarizes emerging therapeutic approaches to prevent or overcome the pathologic effects of tumor-associated fibroblasts.

Abstract

Lung cancer is the leading cause of cancer-related death worldwide. The desmoplastic stroma of lung cancer and other solid tumors is rich in tumor-associated fibroblasts (TAFs) exhibiting an activated/myofibroblast-like phenotype. There is growing awareness that TAFs support key steps of tumor progression and are epigenetically reprogrammed compared to healthy fibroblasts. Although the mechanisms underlying such epigenetic reprogramming are incompletely understood, there is increasing evidence that they involve interactions with either cancer cells, pro-fibrotic cytokines such as TGF-β, the stiffening of the surrounding extracellular matrix, smoking cigarette particles and other environmental cues. These aberrant interactions elicit a global DNA hypomethylation and a selective transcriptional repression through hypermethylation of the TGF-β transcription factor SMAD3 in lung TAFs. Likewise, similar DNA methylation changes have been reported in TAFs from other cancer types, as well as histone core modifications and altered microRNA expression. In this review we summarize the evidence of the epigenetic reprogramming of TAFs, how this reprogramming contributes to the acquisition and maintenance of a tumor-promoting phenotype, and how it provides novel venues for therapeutic intervention, with a special focus on lung TAFs.

Micronutrient Food Supplements in Patients with Gastro-Intestinal and Hepatic Cancers

Colorectal carcinogenesis is the second most common cause of mortality across all types of malignancies, followed by hepatic and stomach cancers. Chemotherapy and radiotherapy are key approaches to treating cancer patients, but these carry major concerns, such as a high risk of side effects, poor accessibility, and the non-selective nature of chemotherapeutics. A number of natural products have been identified as countering various forms of cancer with fewer side effects. The potential impact of vitamins and minerals on long-term health, cognition, healthy development, bone formation, and aging has been supported by experimental and epidemiological studies. Successful treatment may thus be highly influenced by the nutritional status of patients. An insufficient diet could lead to detrimental effects on immune status and tolerance to treatment, affecting the ability of chemotherapy to destroy cancerous cells. In recent decades, most cancer patients have been taking vitamins and minerals to improve standard therapy and/or to decrease the undesirable side effects of the treatment together with the underlying disease. On the other hand, taking dietary supplements during cancer therapy may affect the effectiveness of chemotherapy. Thus, micronutrients in complementary oncology must be selected appropriately and should be taken at the right time. Here, the potential impact of micronutrients on gastro-intestinal and hepatic cancers is explored and their molecular targets are laid down.

An Epigenetic Signature is Associated with Serum 25-Hydroxyvitamin D in Colorectal Cancer Tumors

INTRODUCTION

Vitamin D has been widely associated with colorectal cancer (CRC) through different insights. This study aims to explore the association between serum 25-hydroxyvitamin D (25(OH)D) and the global DNA methylation in tumor from CRC patients.

METHODS AND RESULTS

A genome-wide DNA methylation analysis is conducted in 20 CRC patients under categorical (10 patients have 25(OH)D <30 ng mL^-1 ; 10 patients with 25(OH)D ≥30 ng mL^-1 ) and continuous models of 25(OH)D. A total of 95 differentially methylated CpGs (DMCpGs) are detected under the categorical model (false discovery rate (FDR) < 0.05), while 16 DMCpGs are found under the continuous model. Regional analysis showed eight vitamin D-associated differentially methylated regions (DMR). Between them, a DMR is the most significant at cAMP-Dependent Protein Kinase Inhibitor Alpha (PKIA) locus. Furthermore, seven genes, including PKIA gene, have more or equal than two significant DMCpGs. The protein networking analysis found pathways implicated in cell adhesion and extracellular matrix, as well as signaling transduction.

CONCLUSIONS

This study identifies novel epigenetic loci associated with serum 25(OH)D status. Interestingly, also, a positive association between vitamin D and DNA methylation in the CRC context is found, suggesting a role in CRC. Further studies are warranted to clarify and replicate these results.

Review: Effect of Gut Microbiota and Its Metabolite SCFAs on Radiation-Induced Intestinal Injury

Gut microbiota is regarded as the second human genome and forgotten organ, which is symbiotic with the human host and cannot live and exist alone. The gut microbiota performs multiple physiological functions and plays a pivotal role in host health and intestinal homeostasis. However, the gut microbiota can always be affected by various factors and among them, it is radiotherapy that results in gut microbiota ¹²dysbiosis and it is often embodied in a decrease in the abundance and diversity of gut microbiota, an increase in harmful bacteria and a decrease in beneficial bacteria, thereby affecting many disease states, especially intestine diseases. Furthermore, gut microbiota can produce a variety of metabolites, among which short-chain fatty acids (SCFAs) are one of the most abundant and important metabolites. More importantly, SCFAs can be identified as second messengers to promote signal transduction and affect the occurrence and development of diseases. Radiotherapy can lead to the alterations of SCFAs-producing bacteria and cause changes in SCFAs, which is associated with a variety of diseases such as radiation-induced intestinal injury. However, the specific mechanism of its occurrence is not yet clear. Therefore, this review intends to emphasize the alterations of gut microbiota after radiotherapy and highlight the alterations of SCFAs-producing bacteria and SCFAs to explore the mechanisms of radiation-induced intestinal injury from the perspective of gut microbiota and its metabolite SCFAs.

Vitamin D Toxicity Managed with Peritoneal Dialysis

Vitamin D deficiency is a global health issue that afflicts more than one billion children and adults worldwide. Vitamin D supplementation has increased over the years, whether through medical prescriptions, over-the-counter, or online purchasing. This is driven by a more recognized association between vitamin D sufficiency status and lower risk of cancer. In addition, more recently, it is used as a potential prophylactic and treatment for COVID-19 infection. This can lead to toxicity from overingestion. While rare, it has been reported in the literature. In this case report, we present a 75-year-old man with severe hypercalcemia secondary to vitamin D toxicity managed with peritoneal dialysis. He presented with biochemical evidence of hypercalcemia, acute kidney injury, and pancreatitis. Workup for his hypercalcemia led to the diagnosis of vitamin D toxicity as shown by a level greater than 200 ng/dL (Ref: 20-50 ng/mL) was confirmed by liquid chromatography-mass spectroscopy. Cornerstone medical management of hypercalcemia was provided which included aggressive intravenous fluid hydration, intravenous diuretics, calcitonin, bisphosphonate, and corticosteroid therapy. At every interruption of therapy, calcium levels trended upward. A thorough literature review yielded the finding of a sole case report from 1966 presented at the Third International Congress of Nephrology, in which peritoneal dialysis was used in the management of vitamin D toxicity and hypercalcemia. This modality is established to cause vitamin D deficiency. In collaboration with the nephrology team, 10 sessions of peritoneal dialysis were undertaken with resolution of hypercalcemia and downtrend in 25-hydroxyvitamin D levels as measured by dilution.

Predicting anticancer hyperfoods with graph convolutional networks

Background

Recent efforts in the field of nutritional science have allowed the discovery of disease-beating molecules within foods based on the commonality of bioactive food molecules to FDA-approved drugs. The pioneering work in this field used an unsupervised network propagation algorithm to learn the systemic-wide effect on the human interactome of 1962 FDA-approved drugs and a supervised algorithm to predict anticancer therapeutics using the learned representations. Then, a set of bioactive molecules within foods was fed into the model, which predicted molecules with cancer-beating potential.The employed methodology consisted of disjoint unsupervised feature generation and classification tasks, which can result in sub-optimal learned drug representations with respect to the classification task. Additionally, due to the disjoint nature of the tasks, the employed approach proved cumbersome to optimize, requiring testing of thousands of hyperparameter combinations and significant computational resources.To overcome the technical limitations highlighted above, we represent each drug as a graph (human interactome) with its targets as binary node features on the graph and formulate the problem as a graph classification task. To solve this task, inspired by the success of graph neural networks in graph classification problems, we use an end-to-end graph neural network model operating directly on the graphs, which learns drug representations to optimize model performance in the prediction of anticancer therapeutics.

Results

The proposed model outperforms the baseline approach in the anticancer therapeutic prediction task, achieving an F1 score of 67.99%±2.52% and an AUPR of 73.91%±3.49%. It is also shown that the model is able to capture knowledge of biological pathways to predict anticancer molecules based on the molecules’ effects on cancer-related pathways.

Conclusions

We introduce an end-to-end graph convolutional model to predict cancer-beating molecules within food. The introduced model outperforms the existing baseline approach, and shows interpretability, paving the way to the future of a personalized nutritional science approach allowing the development of nutrition strategies for cancer prevention and/or therapeutics.

Supplementary Information

The online version contains supplementary material available at (10.1186/s40246-021-00333-4).

Vitamin D Intake and the Risk of Colorectal Cancer: An Updated Meta-Analysis and Systematic Review of Case-Control and Prospective Cohort Studies

Obesity, a sedentary lifestyle, high red meat consumption and alcohol, and tobacco are considered the driving factors behind colorectal cancer (CRC) worldwide. Both diet and lifestyle are recognized to play an important role in the prevention of CRC. Forty years later, the vitamin D-cancer hypothesis is considered consistent. However, the relationship between low vitamin D intake and CRC is still controversial. The aim of this meta-analysis is to determine the associations between Vitamin D intake and CRC. MEDLINE-PubMed and Cochrane databases were searched up to May 2020 for studies evaluating the association between vitamin D intake (from foods and supplements) and CRC. Two reviewers, working independently, screened all titles and abstracts to identify the studies that met the inclusion criteria (case-control or prospective cohort (PC) studies published in English). Data were pooled by the generic inverse variance method using a random or fixed effect model. Heterogeneity was identified using the Cochran Q-test and quantified by the I2 statistic. A total of 31 original studies were included for the quantitative meta-analysis, comprising a total 47.540 cases and 70.567 controls in case-control studies, and a total of 14.676 CRC-incident cases (out of 808.130 subjects in PC studies) from 17 countries. A significant 25% lower risk was reported comparing the highest vs. the lowest dietary vitamin D consumption and CRC risk (odds ratio (95% confidence interval): 0.75 (0.67; 0.85)) in case-control studies, whereas a non-significant association was reported in case of prospective studies (hazard ratio (95% confidence interval): 0.94 (0.79; 1.11). The present meta-analysis demonstrates that high dietary vitamin D is associated to CRC prevention. However, larger and high-quality prospective studies and clinical trials are warranted to confirm this association.

Adequacy of calcium and vitamin D reduces inflammation, β-catenin signaling, and dysbiotic Parasutterela bacteria in the colon of C57BL/6 mice fed a western-style diet

Adoption of an obesogenic diet low in calcium and vitamin D (CaD) leads to increased obesity, colonic inflammation, and cancer. However, the underlying mechanisms remain to be elucidated. We tested the hypothesis that CaD supplementation (from inadequacy to adequacy) may reduce colonic inflammation, oncogenic signaling, and dysbiosis in the colon of C57BL/6 mice fed a Western diet. Male C57/BL6 mice (4-weeks old) were assigned to 3 dietary groups for 36 weeks: (1) AIN76A as a control diet (AIN); (2) a defined rodent "new Western diet" (NWD); or (3) NWD with CaD supplementation (NWD/CaD). Compared to the AIN, mice receiving the NWD or NWD/CaD exhibited more than 0.2-fold increase in the levels of plasma leptin, tumor necrosis factor α (TNF-α) and body weight. The levels of plasma interleukin 6 (IL-6), inflammatory cell infiltration, and β-catenin/Ki67 protein (oncogenic signaling) were increased more than 0.8-fold in the NWD (but not NWD/CaD) group compared to the AIN group. Consistent with the inflammatory phenotype, colonic secondary bile acid (inflammatory bacterial metabolite) levels increased more than 0.4-fold in the NWD group compared to the NWD/CaD and AIN groups. Furthermore, the abundance of colonic Proteobacteria (e.g., Parasutterela), considered signatures of dysbiosis, was increased more than four-fold; and the α diversity of colonic bacterial species, indicative of health, was decreased by 30% in the NWD group compared to the AIN and NWD/CaD groups. Collectively, CaD adequacy reduces colonic inflammation, β-catenin oncogenic signaling, secondary bile acids, and bacterial dysbiosis in mice fed with a Western diet.

Identification of Vitamin D-related gene signature to predict colorectal cancer prognosis

Colorectal cancer (CRC) is one of the most common malignant carcinomas worldwide with poor prognosis, imposing an increasingly heavy burden on patients. Previous experiments and epidemiological studies have shown that vitamin D and vitamin D-related genes play a vital role in CRC. Therefore, we aimed to construct a vitamin D-related gene signature to predict prognosis in CRC. The CRC data from The Cancer Genome Atlas (TCGA) was performed as the training set. A total of 173 vitamin D-related genes in the TCGA CRC dataset were screened, and 17 genes associated with CRC prognosis were identified from them. Then, a vitamin D-related gene signature consisting of those 17 genes was established by univariate and multivariate Cox analyses. Moreover, four external datasets (GSE17536, GSE103479, GSE39582, and GSE17537) were used as testing set to validate the stability of this signature. The high-risk group presented a significantly poorer overall survival than low-risk group in both of training set and testing sets. Besides, the areas under the curve (AUCs) for signature on OS in training set at 1, 3, and 5 years were 0.710, 0.708, 0.710 respectively. The AUCs of the ROC curve in GSE17536 for 1, 3, and 5 years were 0.649, 0.654, and 0.694. These results indicated the vitamin D-related gene signature model could effectively predict the survival status of CRC patients. This vitamin D-related gene signature was also correlated with TNM stage in CRC clinical parameters, and the higher risk score from this model was companied with higher clinical stage. Furthermore, the high accuracy of this prognostic signature was validated and confirmed by nomogram model. In conclusion, we have proposed a novel vitamin D-related gene model to predict the prognosis of CRC, which will help provide new therapeutic targets and act as potential prognostic biomarkers for CRC.

Newly-identified Pathways Relating Vitamin D to Carcinogenesis: A Review

BACKGROUND

The epidemiological relationship between vitamin D levels and cancer has been thoroughly investigated. Published data from large studies appear to corroborate a significant relationship between higher serum vitamin D concentrations and improved survival. Mechanistic reviews on commonly-studied cancers - including breast cancer, colon cancer and melanoma - focus predominantly on data from older studies. In outlining avenues for future research, we believe there is utility in summarizing novel findings introduced to the literature.

MATERIALS AND METHODS

In this narrative review, we used MEDLINE, PUBMED and Cochrane databases to identify mechanistic studies published from January 1, 2015 onwards exploring this topic.

RESULTS

Twenty-five mechanistic studies were included in this review. It was found that vitamin D plays a critical role in both direct (i.e. tumor gene expression, proliferation, invasiveness, sensitivity to chemotherapy etc.) and indirect (i.e. effects on the tumor microenvironment and immunomodulation) tumor suppression mechanisms.

CONCLUSION

These newly-identified pathways warrant further research, with the hopes that we may understand how and when vitamin D supplementation can be integrated into precision medicine therapeutics for cancers of the breast, colon and skin. Cancer care providers should consider recommendations to screen for vitamin D deficiency in this population.

Genomic and epigenomic active vitamin D responses in human colonic organoids

Active vitamin D, 1α,25(OH)₂D₃, is a nuclear hormone with roles in colonic homeostasis and carcinogenesis; yet, mechanisms underlying these effects are incompletely understood. Human organoids are an ideal system to study genomic and epigenomic host-environment interactions. Here, we use human colonic organoids to measure 1α,25(OH)₂D₃ responses on genome-wide gene expression and chromatin accessibility over time. Human colonic organoids were cultured and treated in triplicate with 100 nM 1α,25(OH)₂D₃ or vehicle control for 4 h and 18 h for chromatin accessibility, and 6 h and 24 h for gene expression. ATAC- and RNA-sequencing were performed. Differentially accessible peaks were analyzed using DiffBind and edgeR; differentially expressed genes were analyzed using DESeq2. Motif enrichment was determined using HOMER. At 6 h and 24 h, 2,870 and 2,721 differentially expressed genes, respectively (false discovery rate, FDR < 5%), were identified with overall stronger responses with 1α,25(OH)₂D₃. Similarly, 1α,25(OH)₂D₃ treatment led to stronger chromatin accessibility especially at 4 h. The vitamin D receptor (VDR) motif was strongly enriched among accessible chromatin peaks with 1α,25(OH)₂D₃ treatment accounting for 30.5% and 11% of target sequences at 4 h and 18 h, respectively (FDR < 1%). A number of genes such as CYP24A1, FGF19, MYC, FOS, and TGFBR2 showed significant transcriptional and chromatin accessibility responses to 1α,25(OH)₂D₃ treatment with accessible chromatin located distant from promoters for some gene regions. Assessment of chromatin accessibility and transcriptional responses to 1α,25(OH)₂D₃ yielded new observations about vitamin D genome-wide effects in the colon facilitated by application of human colonic organoids. This framework can be applied to study host-environment interactions between individuals and populations in the future.

The Role of Gut Barrier Dysfunction and Microbiome Dysbiosis in Colorectal Cancer Development

Accumulating evidence indicates that breakdown of the+ protective mucosal barrier of the gut plays a role in colorectal cancer (CRC) development. Inflammation and oxidative stress in the colonic epithelium are thought to be involved in colorectal carcinogenesis and the breakdown of the integrity of the colonic barrier may increase the exposure of colonocytes to toxins from the colonic milieu, enhancing inflammatory processes and release of Reactive Oxygen Species (ROS). The aetiological importance of the gut microbiome and its composition - influenced by consumption of processed meats, red meats and alcoholic drinks, smoking, physical inactivity, obesity - in CRC development is also increasingly being recognized. The gut microbiome has diverse roles, such as in nutrient metabolism and immune modulation. However, microbial encroachment towards the colonic epithelium may promote inflammation and oxidative stress and even translocation of species across the colonic lumen. Recent research suggests that factors that modify the above mechanisms, e.g., obesity and Western diet, also alter gut microbiota, degrade the integrity of the gut protective barrier, and expose colonocytes to toxins. However, it remains unclear how obesity, lifestyle and metabolic factors contribute to gut-barrier integrity, leading to metabolic disturbance, colonocyte damage, and potentially to CRC development. This review will discuss the interactive roles of gut-barrier dysfunction, microbiome dysbiosis, and exposure to endogenous toxins as another mechanism in CRC development, and how biomarkers of colonic mucosal barrier function may provide avenues for disease, prevention and detection.