Vitamin A and cancer

Inhibition of retinoic acid signaling in proximal tubular epithelial cells protects against acute kidney injury

Retinoic acid receptor (RAR) signaling is essential for mammalian kidney development but, in the adult kidney, is restricted to occasional collecting duct epithelial cells. We now show that there is widespread reactivation of RAR signaling in proximal tubular epithelial cells (PTECs) in human sepsis-associated acute kidney injury (AKI) and in mouse models of AKI. Genetic inhibition of RAR signaling in PTECs protected against experimental AKI but was unexpectedly associated with increased expression of the PTEC injury marker Kim1. However, the protective effects of inhibiting PTEC RAR signaling were associated with increased Kim1-dependent apoptotic cell clearance, or efferocytosis, and this was associated with dedifferentiation, proliferation, and metabolic reprogramming of PTECs. These data demonstrate the functional role that reactivation of RAR signaling plays in regulating PTEC differentiation and function in human and experimental AKI.

Inhibition of Retinoic Acid Signaling in Proximal Tubular Epithelial cells Protects against Acute Kidney Injury by Enhancing Kim-1-dependent Efferocytosis

Retinoic acid receptor (RAR) signaling is essential for mammalian kidney development, but in the adult kidney is restricted to occasional collecting duct epithelial cells. We now show there is widespread reactivation of RAR signaling in proximal tubular epithelial cells (PTECs) in human sepsis-associated acute kidney injury (AKI), and in mouse models of AKI. Genetic inhibition of RAR signaling in PTECs protects against experimental AKI but is associated with increased expression of the PTEC injury marker, Kim-1. However, Kim-1 is also expressed by de-differentiated, proliferating PTECs, and protects against injury by increasing apoptotic cell clearance, or efferocytosis. We show that the protective effect of inhibiting PTEC RAR signaling is mediated by increased Kim-1 dependent efferocytosis, and that this is associated with de-differentiation, proliferation, and metabolic reprogramming of PTECs. These data demonstrate a novel functional role that reactivation of RAR signaling plays in regulating PTEC differentiation and function in human and experimental AKI.

Graphical abstract

The association between maternal nutrient intake during pregnancy and the risk of sporadic unilateral retinoblastoma among offspring

Previous studies have associated maternal diet during pregnancy with the development of sporadic unilateral retinoblastoma (RB), but few studies have focused on the role of individual nutrients. The aim of this study is to investigate the association between maternal nutrient intake during pregnancy and the development of sporadic unilateral RB in the offspring. A modified food frequency questionnaire, with additional questions on supplement use, was completed via a phone interview. Cases were recruited from hospitals and controls were comprised of friends and relatives of the patient without a history of cancer. Overall, 168 sporadic unilateral RB cases and 145 controls were included in case-control study. We performed logistic regression to estimate odds ratios (ORs) and 95 % confidence intervals (CI), adjusting for child's age, child's sex, parental race/ethnicity, maternal education, total calorie intake during pregnancy, maternal age at birth, maternal smoking during pregnancy, pre-pregnancy body mass index, maternal weight gain during pregnancy, paternal age at birth, and maternal multivitamin use in the year before pregnancy. In the adjusted model, the interquartile (IQR) increase in vitamin A intake, which was measured in retinol activity equivalent (RAE; OR: 0.64, 95 % CI: 0.46-0.90), and vitamin D intake (OR: 0.62, 95 % CI: 0.42-0.91) significantly reduced the risk of sporadic unilateral RB. These findings suggest that a higher intake of vitamins A and D can be a protective factor for sporadic unilateral RB. Further analyses in consideration of multi-exposures such as parental occupational exposures are warranted to discover the complex etiology of sporadic unilateral RB. In addition, the role of nutritional epigenetics for how maternal nutrient intake influences the risk of sporadic unilateral RB in the offspring still needs to be explored.

Vitamins as Possible Cancer Biomarkers: Significance and Limitations

The Western-style diet, which is common in developed countries and spreading into developing countries, is unbalanced in many respects. For instance, micronutrients (vitamins A, B complex, C, D, E, and K plus iron, zinc, selenium, and iodine) are generally depleted in Western food (causing what is known as ‘hidden hunger’), whereas some others (such as phosphorus) are added beyond the daily allowance. This imbalance in micronutrients can induce cellular damage that can increase the risk of cancer. Interestingly, there is a large body of evidence suggesting a strong correlation between vitamin intake as well as vitamin blood concentrations with the occurrence of certain types of cancer. The direction of association between the concentration of a given vitamin and cancer risk is tumor specific. The present review summarized the literature regarding vitamins and cancer risk to assess whether these could be used as diagnostic or prognostic markers, thus confirming their potential as biomarkers. Despite many studies that highlight the importance of monitoring vitamin blood or tissue concentrations in cancer patients and demonstrate the link between vitamin intake and cancer risk, there is still an urgent need for more data to assess the effectiveness of vitamins as biomarkers in the context of cancer. Therefore, this review aims to provide a solid basis to support further studies on this promising topic.

Vitamin A supplementation ameliorates ulcerative colitis in gut microbiota-dependent manner

Ulcerative colitis (UC), is a chronic relapsing inflammatory condition of the gastrointestinal track. The purpose of this study is to explore whether Vitamin A (V_A) can treat UC and its mechanisms. A mouse model of UC was established using 3.0% (w/v) dextran sodium sulfate (DSS). V_A was used to treat UC by intragastric administration of 5000 international unit (IU) retinyl acetate. Fecal microbiota transplantation (FMT) was also used to treat the UC model mice to verify the effect of influenced gut microbiota. The content of short-chain fatty acids (SCFAs) in cecal contents was quantitatively detected by gas chromatography and mass spectrometry. V_A supplementation significantly ameliorated UC. 16S rRNA sequencing indicated that V_A-treated mice exhibited much more abundant gut microbial diversity and flora composition. Targeted metabolomics analysis manifested the increased production of SCFAs in V_A-treated mice. Gut microbiota depletion and FMT results confirmed the gut microbiota-dependent mechanism as that V_A relieved UC via regulating gut microbiota: increase in SCFA-producing genera and decrease in UC-related genera. The restore of intestinal barrier and the inhibition of inflammation were also found to contribute to the amelioration of UC by V_A. It was concluded that a V_A supplement was enough to cause a significant change in gut microbiota and amelioration of UC.

An Updated Comprehensive Review on Vitamin A and Carotenoids in Breast Cancer: Mechanisms, Genetics, Assessment, Current Evidence, and Future Clinical Implications

Vitamin A and carotenoids are fat-soluble micronutrients that play important role as powerful antioxidants modulating oxidative stress and cancer development. Breast cancer is the most common malignancy in women. As the risk of breast cancer is dependent on various lifestyle factors such as dietary modifications, there is increasing interest surrounding the anti-cancerous properties of vitamin A and carotenoids. Despite the suggested protective roles of vitamin A and carotenoids in breast cancer development, their clinical application for the prevention and treatment of breast cancer is limited. In this narrative review, we discuss the roles of vitamin A and carotenoids along with the evaluation method of vitamin A status. We also exhibit the association of genetic variations involved in metabolism of vitamin A and carotenoids with cancers and other diseases. We demonstrate the epidemiological evidence for the relationship of vitamin A and carotenoids with breast cancer risk, their effects on cancer mechanism, and the recent updates in clinical practice of vitamin A or carotenoids as a potential therapeutic agent against breast cancer. This review provides insight into the preventive and therapeutic roles of vitamin A and carotenoids in breast cancer development and progression.

Clinical characterization and therapeutic targets of vitamin A in patients with hepatocholangiocarcinoma and coronavirus disease

Recent reports indicate that patients with hepatocholangiocarcinoma (CHOL) have a higher morbidity and mortality rate for coronavirus disease (COVID-19). Anti-CHOL/COVID-19 medicines are inexistent. Vitamin A (VA) refers to a potent nutrient with anti-cytotoxic and anti-inflammatory actions. Therefore, this study aimed to determine the potential functions and molecular mechanisms of VA as a potential treatment for patients with both CHOL and COVID-19 (CHOL/COVID-19). The transcriptome data of CHOL patients were obtained from the Cancer Genome Analysis database. Furthermore, the network pharmacology approach and bioinformatics analysis were used to identify and reveal the molecular functions, therapeutic biotargets, and signaling of VA against CHOL/COVID-19. First, clinical findings identified the medical characteristics of CHOL patients with COVID-19, such as susceptibility gene, prognosis, recurrence, and survival rate. Anti-viral and anti-inflammatory pathways, and immunopotentiation were found as potential targets of VA against CHOL/COVID-19. These findings illustrated that VA may contribute to the clinical management of CHOL/COVID-19 achieved by induction of cell repair, suppression of oxidative stress and inflammatory reaction, and amelioration of immunity. Nine vital therapeutic targets (BRD2, NOS2, GPT, MAPK1, CXCR3, ICAM1, CDK4, CAT, and TMPRSS13) of VA against CHOL/COVID-19 were identified. For the first time, the potential pharmacological biotargets, function, and mechanism of action of VA in CHOL/COVID-19 were elucidated.

Chemoprevention of Colorectal Cancer

Although colorectal cancer (CRC) screening has reduced the incidence of and mortality from CRC, chemoprevention strategies have the potential to further reduce CRC incidence and mortality. Chemoprevention agents might be used for average-risk as well as high-risk groups, and to prevent CRC recurrence after therapy. CRC chemoprevention agents that have been studied include aspirin, nonaspirin nonsteroidal anti-inflammatory drugs, statins, agents that target metabolic pathways, and vitamins and minerals. We review the prospect of chemoprevention of CRC, results from preclinical and human studies, challenges, and future directions.

Microalgal Derivatives as Potential Nutraceutical and Food Supplements for Human Health: A Focus on Cancer Prevention and Interception

Epidemiological studies are providing strong evidence on beneficial health effects from dietary measures, leading scientists to actively investigate which foods and which specific agents in the diet can prevent diseases. Public health officers and medical experts should collaborate toward the design of disease prevention diets for nutritional intervention. Functional foods are emerging as an instrument for dietary intervention in disease prevention. Functional food products are technologically developed ingredients with specific health benefits. Among promising sources of functional foods and chemopreventive diets of interest, microalgae are gaining worldwide attention, based on their richness in high-value products, including carotenoids, proteins, vitamins, essential amino acids, omega-rich oils and, in general, anti-inflammatory and antioxidant compounds. Beneficial effects of microalgae on human health and/or wellness could in the future be useful in preventing or delaying the onset of cancer and cardiovascular diseases. During the past decades, microalgal biomass was predominately used in the health food market, with more than 75% of the annual microalgal biomass production being employed for the manufacture of powders, tablets, capsules or pastilles. In this review, we report and discuss the present and future role of microalgae as marine sources of functional foods/beverages for human wellbeing, focusing on perspectives in chemoprevention. We dissected this topic by analyzing the different classes of microalgal compounds with health outputs (based on their potential chemoprevention activities), the biodiversity of microalgal species and how to improve their cultivation, exploring the perspective of sustainable food from the sea.

Dose-Response Relationship between Serum Retinol Levels and Survival in Patients with Colorectal Cancer: Results from the DACHS Study

Current knowledge on the role of retinol in the prognosis of patients with colorectal cancer (CRC) is very limited. We investigated the association of serum retinol levels with survival outcomes in a large cohort of 2908 CRC patients from Germany. Retinol concentrations were determined in serum collected shortly after diagnosis by mass spectrometry. Associations between serum retinol levels and survival outcomes were assessed using multivariable Cox regression and dose-response analyses. The joint association of serum retinol and serum 25-hydroxyvitamin D₃ (25(OH)D₃) with survival outcomes was also examined. During a median follow-up of 4.8 years, 787 deaths occurred, 573 of which were due to CRC. Dose-response curves showed an inverse relationship between serum retinol levels and survival endpoints in the range of <2.4 µmol/L, but no associations at higher levels. Low (<1.2 µmol/L) versus high (≥2.4 µmol/L) serum retinol levels were associated with poorer overall survival (Hazard ratio (HR) = 1.46, 95% confidence interval (CI) = 1.19–1.78, P-trend = 0.0003) and CRC-specific survival (HR = 1.69, 95% CI = 1.33–2.15, P-trend < 0.0001). Joint presence of low serum retinol (<1.2 µmol/L) and low 25(OH)D₃ (<30 nmol/L) was associated with a particularly strong decrease in overall and CRC-specific survival. Low serum retinol levels were identified as a predictor of poor survival in CRC patients, in particular when co-occurring with low serum concentrations of 25(OH)D₃. The clinical implications of these findings require further investigation.

Novel Insights into the Pathogenesis of Monogenic Congenital Anomalies of the Kidney and Urinary Tract

Congenital anomalies of the kidneys and urinary tract (CAKUT) comprise a large spectrum of congenital malformations ranging from severe manifestations, such as renal agenesis, to potentially milder conditions, such as vesicoureteral reflux. CAKUT causes approximately 40% of ESRD that manifests within the first three decades of life. Several lines of evidence indicate that CAKUT is often caused by recessive or dominant mutations in single (monogenic) genes. To date, approximately 40 monogenic genes are known to cause CAKUT if mutated, explaining 5%-20% of patients. However, hundreds of different monogenic CAKUT genes probably exist. The discovery of novel CAKUT-causing genes remains challenging because of this pronounced heterogeneity, variable expressivity, and incomplete penetrance. We here give an overview of known genetic causes for human CAKUT and shed light on distinct renal morphogenetic pathways that were identified as relevant for CAKUT in mice and humans.

Vitamin A, cancer treatment and prevention: the new role of cellular retinol binding proteins

Retinol and vitamin A derivatives influence cell differentiation, proliferation, and apoptosis and play an important physiologic role in a wide range of biological processes. Retinol is obtained from foods of animal origin. Retinol derivatives are fundamental for vision, while retinoic acid is essential for skin and bone growth. Intracellular retinoid bioavailability is regulated by the presence of specific cytoplasmic retinol and retinoic acid binding proteins (CRBPs and CRABPs). CRBP-1, the most diffuse CRBP isoform, is a small 15 KDa cytosolic protein widely expressed and evolutionarily conserved in many tissues. CRBP-1 acts as chaperone and regulates the uptake, subsequent esterification, and bioavailability of retinol. CRBP-1 plays a major role in wound healing and arterial tissue remodelling processes. In the last years, the role of CRBP-1-related retinoid signalling during cancer progression became object of several studies. CRBP-1 downregulation associates with a more malignant phenotype in breast, ovarian, and nasopharyngeal cancers. Reexpression of CRBP-1 increased retinol sensitivity and reduced viability of ovarian cancer cells in vitro. Further studies are needed to explore new therapeutic strategies aimed at restoring CRBP-1-mediated intracellular retinol trafficking and the meaning of CRBP-1 expression in cancer patients' screening for a more personalized and efficacy retinoid therapy.

Intakes of vitamins A, C, and E and use of multiple vitamin supplements and risk of colon cancer: a pooled analysis of prospective cohort studies

OBJECTIVE

To evaluate the associations between intakes of vitamins A, C, and E and risk of colon cancer.

METHODS

Using the primary data from 13 cohort studies, we estimated study- and sex-specific relative risks (RR) with Cox proportional hazards models and subsequently pooled RRs using a random effects model.

RESULTS

Among 676,141 men and women, 5,454 colon cancer cases were identified (7-20 years of follow-up across studies). Vitamin A, C, and E intakes from food only were not associated with colon cancer risk. For intakes from food and supplements (total), the pooled multivariate RRs (95% CI) were 0.88 (0.76-1.02, >4,000 vs. ≤ 1,000 μg/day) for vitamin A, 0.81 (0.71-0.92, >600 vs. ≤ 100 mg/day) for vitamin C, and 0.78 (0.66-0.92, > 200 vs. ≤ 6 mg/day) for vitamin E. Adjustment for total folate intake attenuated these associations, but the inverse associations with vitamins C and E remained significant. Multivitamin use was significantly inversely associated with colon cancer risk (RR = 0.88, 95% CI: 0.81-0.96).

CONCLUSIONS

Modest inverse associations with vitamin C and E intakes may be due to high correlations with folate intake, which had a similar inverse association with colon cancer. An inverse association with multivitamin use, a major source of folate and other vitamins, deserves further study.

Metabolism and regulation of gene expression by 4-oxoretinol versus all-trans retinoic acid in normal human mammary epithelial cells

We previously demonstrated that 4-oxoretinol (4-oxo-ROL) activated retinoic acid receptors (RARs) in F9 stem cells. We showed that 4-oxo-ROL inhibited the proliferation of normal human mammary epithelial cells (HMECs). To understand the mechanisms by which 4-oxo-ROL regulates HMEC growth we examined gene expression profiles following 4-oxo-ROL or all-trans retinoic acid (tRA). We also compared growth inhibition by tRA, 4-oxo-ROL, or 4-oxo-RA. All three retinoids inhibited HMEC proliferation. Gene expression analyses indicated that 4-oxo-ROL and tRA modulated gene expression in closely related pathways. The expression of many genes, e.g. ATP-binding cassette G1 (ABCG1); adrenergic receptorbeta2 (ADRB2); ras-related C3 botulinum toxin substrate (RAC2); and short-chain dehydrogenase/reductase 1 gene (SDR1) was changed after 4-oxo-ROL or tRA. Metabolism of these retinoids was analyzed by high-performance liquid chromatography (HPLC). In 1 microM tRA treated HMECs all of the tRA was found intracellularly, and tRA was the predominant intracellular retinoid. In 1 microM 4-oxo-ROL treated HMECs most 4-oxo-ROL was esterified to 4-oxoretinyl esters, no tRA was detected, and 4-oxo-ROL and 4-oxo-RA were observed intracellularly. In 1 microM 4-oxoretinoic acid (4-oxo-RA) treated HMECs little intracellular 4-oxo-RA was detected; most 4-oxo-RA was in the medium. Our results indicate that: (a) 4-oxo-ROL regulates gene expression and inhibits proliferation of HMECs; (b) 4-oxo-ROL and tRA regulate some of the same genes; (c) more tRA is found in cells, as compared to 4-oxoretinoic acid, when each drug is added at the same concentration in the medium; and (d) the mechanism by which 4-oxo-ROL exerts its biological activity does not involve intracellular tRA production.

Overexpression of lecithin:retinol acyltransferase in the epithelial basal layer makes mice more sensitive to oral cavity carcinogenesis induced by a carcinogen

Lecithin:retinol acyltransferase (LRAT) is an enzyme that converts retinol (vitamin A) to retinyl esters. Its expression is often reduced in human cancers, including oral cavity cancers. We investigated the effects of ectopic expression of human lecithin:retinol acyltransferase (LRAT) on murine oral cavity carcinogenesis induced by the carcinogen 4-nitroquinoline 1-oxide (4-NQO). We targeted human LRAT expression specifically to the basal layer of mouse skin and oral cavity epithelia by using a portion of the human cytokeratin 14 (K14) promoter. High levels of human LRAT transgene transcripts were detected in the tongues and skin of adult transgenic positive (TG+) mice, but not in transgenic negative (TG-) mice. The retinyl ester levels in skin of LRAT TG+ mice were 32% +/- 5.4% greater than those in TG- mice, and topical treatment of the back skin with retinol resulted in greater increases in retinyl esters (from 6.9- to 14.3-fold in different TG+ mice) in TG+ mouse skin than in TG- mouse skin (1.3 fold). While carcinogen (4-NQO) treatment induced multifocal precancerous and cancer lesions in the tongues of both TG positive (n=16) and negative mice (n=22), higher percentages of transgenic positive mice (62.5%) developed more severe tongue lesions (grades 3 and 4) than transgenic negative mice (24.8%) after 4-NQO treatment (p < 0.05). Carcinogen treatment also resulted in greater percentages of transgenic positive mouse tongues with hyperplasia (71.4%), dysplasia (85.7%, p < 0.05), and carcinoma (28.6%) than transgenic negative mouse tongues (53.3%, 46.7%, and 20%, respectively). Moreover, we observed higher cyclooxygenase-2 (Cox-2) and lower RARbeta(2) mRNA levels in TG+ mouse tongues as compared to TG- mouse tongues after 4-NQO treatment (p < 0.05). Taken together, these data show that overexpression of human LRAT specifically in oral basal epithelial cells makes these cells more sensitive to carcinogen induced tumorigenesis.

SOX9 mediates the retinoic acid-induced HES-1 gene expression in human breast cancer cells

We have previously shown that the anti-proliferative effect of retinoic acid in human breast cancer cell line MCF-7 is dependent on HES-1 expression. Here we show that retinoic acid induces HES-1 expression via upregulation of transcription factor SOX9. By expressing a dominant negative form of SOX9, disrupting endogenous SOX9 activity, the retinoic acid-induced HES-1 mRNA expression was inhibited. We found an enhancer regulating HES-1 expression: two SOX9 binding sites upstream of the HES-1 gene that were capable of binding SOX9 in vitro. By performing chromatin immunoprecipitation, we showed that SOX9 binding to the HES-1 enhancer was induced by retinoic acid in vivo. In reporter assays, transfection of a SOX9 expression plasmid increased the activity of the HES-1 enhancer. The enhancer responded to retinoic acid; furthermore, the expression of a dominant negative SOX9 abolished this response. Taken together, we present here a novel transcriptional mechanism in regulating hormone-dependent cancer cell proliferation.

Retinoic acid decreases ATF-2 phosphorylation and sensitizes melanoma cells to taxol-mediated growth inhibition

Cutaneous melanoma is often resistant to chemo- and radiotherapy. This resistance has recently been demonstrated to be due, at least in part, to high activating transcription factor 2 (ATF-2) activity in these tumors. In concordance with these reports, we found that B16 mouse melanoma cells had higher levels of ATF-2 than immortalized, but non-malignant mouse melanocytes. In addition, the melanoma cells had a much higher amount of phosphorylated (active) ATF-2 than the immortalized melanocytes. In the course of determining how retinoic acid (RA) stimulates activating protein-1 (AP-1) activity in B16 melanoma, we discovered that this retinoid decreased the phosphorylation of ATF-2. It appears that this effect is mediated through p38 MAPK, because RA decreased p38 phosphorylation, and a selective inhibitor of p38 MAPK (SB203580) also inhibited the phosphorylation of ATF-2. Since ATF-2 activity appears to be involved in resistance of melanoma to chemotherapy, we tested the hypothesis that treatment of the melanoma cells with RA would sensitize them to the growth-inhibitory effect of taxol. We found that pretreatment of B16 cells with RA decreased the IC50 from 50 nM to 1 nM taxol. On the basis of these findings and our previous work on AP-1, we propose a model in which treatment of B16 cells with RA decreases the phosphorylation of ATF-2, which results in less dimer formation with Jun. The "freed-up" Jun can then form a heterodimer with Fos, resulting in the increased AP-1 activity observed in RA-treated B16 cells. Shifting the balance from predominantly ATF-2:Jun dimers to a higher amount of Jun:Fos dimers could lead a change in target gene expression that reduces resistance to chemotherapeutic drugs and contributes to the pathway by which RA arrests proliferation and induces differentiation.

Melanoma chemoprevention

BACKGROUND

Despite efforts to promote sun protection behaviors, melanoma incidence continues to increase. The prognosis of advanced melanoma remains extremely poor in spite of treatment advances, emphasizing the importance of exploring additional preventive measures.

OBJECTIVE

We sought to summarize the results of published research on candidate chemoprevention agents for melanoma.

METHODS

We conducted a narrative review of the literature.

RESULTS

Investigation into a possible role in melanoma chemoprevention continues for multiple agents, including sunscreen, lipid-lowering medications, nonsteroidal anti-inflammatory drugs, dietary nutrients, immunomodulators, and other drugs, including retinoids, difluoromethylornithine, and T4 endonuclease V.

LIMITATIONS

Systematic review of the literature was not performed.

CONCLUSION

Because no agent yet emerges as a clear choice for effective melanoma chemoprevention, sun avoidance and sun protection remain the mainstay of melanoma prevention for persons at high risk.

Alterations in gene expression in rat skin exposed to 56Fe ions and dietary vitamin A acetate

The purpose of the present work was to examine gene expression patterns in rat skin exposed to a beam of (56)Fe ions, a surrogate for the high-energy, heavy-ion galactic radiation background, as a basis for obtaining a better understanding of the possible mechanism(s) behind the radioprotective activity of vitamin A. A 2 x 4-cm rectangle of dorsal rat skin was exposed to 1.01 GeV/nucleon (56)Fe ions generated by the Alternating Gradient Synchrotron at Brookhaven National Laboratory. Gene expression patterns were monitored in either the presence or absence of a 250-ppm dietary supplement of vitamin A acetate in powdered lab chow. Although vitamin A and other retinoids show anti-carcinogenic activity in several animal models, the underlying changes in gene expression have not been examined extensively. At either 1 or 7 day after irradiation, a 1-cm square of irradiated and control rat skin was excised and analyzed using the Affymetrix rat microarray (RG_U34A) system. Microarray responses were displayed and processed by GeneSpring 7.0 and GOTree software. At 1 day after 3 Gy of (56)Fe-ion irradiation, the expression of 110 genes was significantly up-regulated (P < = 0.05) in comparison to levels in control rat skin, while no genes were altered by the vitamin A acetate supplement alone. Combined with (56)Fe-ion radiation, the vitamin A acetate supplement blocked the expression of 88 (80%) of the 110 genes and eliminated 16 of 18 gene categories that were significantly altered (all increased) by the (56)Fe-ion radiation. Categories with large numbers of genes eliminated by the retinoid included response to stress, 33 genes; response to biotic stimulus, 38 genes; signal transduction, 35 genes; and regulation of cellular/physiological process, 40 genes. Even for immune response and response to biotic stimulus, the only two categories that remained significantly altered in the presence of the vitamin, the combined number of altered genes was reduced from 74 to 13. No significant alterations in gene expression were found at 7 days relative to the numbers in controls. The results indicate that at 1 day dietary vitamin A acetate strongly interfered with (56)Fe-ion-induced gene expression within the broad categories of stimulus- and stress-related genes, implying that the latter gene categories likely play a role in the radioprotective action of the vitamin.

Relationship between nutritional habits adopted by ulcerative colitis relevant to cancer development patients at clinical remission stages and molecular-genetic parameters

UC (ulcerative colitis) patients have an increased risk of developing colorectal cancer compared with the normal population. The cause underlying this higher risk is not fully defined but includes nutritional and environmental factors concomitant with genetic alterations. We aimed to evaluate genetic stability in the colonic tissue of UC patients in clinical remission compared with the healthy population, and to establish a possible correlation between nutritional habits and these molecular assessments. UC patients (n 42) and healthy controls (n 37) participated in the study. All participants were histopathologically and medically diagnosed. Participants completed five separate 7 d dietary records, food-frequency questionnaires and validated 24 h recalls for nutritional assessment. The extent of chromosome 17 loss and the calculated chromosome index was determined in colon tissue biopsies by fluorescence in situ hybridisation. Correlations between the molecular and nutritional assessments were performed using Pearson's correlation coefficients. Significant differences in the nutritional intake of total fat (65 (SD 15) v. 89 (SD 25) g), cholesterol (330 (SD 168) v. 464 (SD 177) mg), dietary fibre (32 (SD 4.7) v. 9 (SD 4) g), vitamin A (1009 (SD 209) v. 506 (SD 204) microg), vitamin C (308 (SD 108) v. 72 (SD 53) mg) and folic acid (412 (SD 89 microg) v. 187 (SD 107)) were recorded for UC patients compared with controls. Significant correlations were found for the consumption of different food groups and the chromosome index for chromosome 17. The results of our study suggest that the nutritional habits adopted by UC patients during clinical remission may affect key cellular components of the colonic tissue, inducing a high degree of aneuploidy and genetic instability, and probably affecting the development of colon cancer.

Different effect of beta-carotene on proliferation of prostate cancer cells

It was shown that high doses of beta-carotene (>30 microM) decrease proliferation of prostate cancer cells in vitro. However, it is rather doubtful whether such concentration of beta-carotene is really accessible at cellular level. We studied the effect of 3 and 10 microM beta-carotene on proliferation and gene expression in LNCaP and PC-3 prostate cancer cell lines. Beta-carotene--more efficiently absorbed from medium by androgen-sensitive LNCaP cells--increased proliferation of LNCaP cells whereas it had weaker effect on PC-3 cells. Initial global analysis of expression of genes in both cell lines treated with 10 microM beta-carotene (Affymetrix HG-U133A) showed remarkable differences in number of responsive genes. Their recognition allows for conclusion that differences between prostate cancer cell lines in response to beta-carotene treatment are due to various androgen sensitivities of LNCaP and PC-3 cells. Detailed analysis of expression of selected genes in beta-carotene treated LNCaP cells at the level of mRNA and protein indicated that the observed increase of proliferation could have been the result of slight induction of a few genes affecting proliferation (c-myc, c-jun) and apoptosis (bcl-2) with no significant effect on major cell cycle control genes (cdk2, RB, E2F-1).

Alcohol in hepatocellular cancer

Hepatocellular cancer accounts for almost half a million cancer deaths a year, with an escalating incidence in the Western world. Alcohol has long been recognized as a major risk factor for cancer of the liver and of other organs including oropharynx, larynx, esophagus, and possibly the breast and colon. There is compelling epidemiologic data confirming the increased risk of cancer associated with alcohol consumption, which is supported by animal experiments. Cancer of the liver associated with alcohol usually occurs in the setting of cirrhosis. Alcohol may act as a cocarcinogen, and has strong synergistic effects with other carcinogens including hepatitis B and C, aflatoxin, vinyl chloride, obesity, and diabetes mellitus. Acetaldehyde, the main metabolite of alcohol, causes hepatocellular injury, and is an important factor in causing increased oxidant stress, which damages DNA. Alcohol affects nutrition and vitamin metabolism, causing abnormalities of DNA methylation. Abnormalities of DNA methylation, a key pathway of epigenetic gene control, lead to cancer. Other nutritional and metabolic effects, for example on vitamin A metabolism, also play a key role in hepatocarcinogenesis. Alcohol enhances the effects of environmental carcinogens directly and by contributing to nutritional deficiency and impairing immunological tumor surveillance. This review summarizes the epidemiologic evidence for the role of alcohol in hepatocellular cancer, and discusses the mechanisms involved in the promotion of cancer.

Signaling pathways in retinoid chemoprevention and treatment of cancer

The Vitamin A metabolite, retinoic acid, has been shown to have chemopreventive and therapeutic activity for certain cancers such as head and neck, cervical, neuroblastoma and promyelocytic leukemia. Retinoic acid achieves these activities by inducing differentiation and/or growth arrest. A large number of studies have investigated the mechanism(s) by which retinoic acid alters the behavior of premalignant and tumor cells. Although much important data has been obtained, the exact signaling pathways required for retinoic acid to exert its biological effects remains elusive. In this review, we outline the role and function of retinoid nuclear receptors, followed by a discussion of how major signaling pathways are affected in different tumor types by retinoids. We conclude by examining the effect of retinoic acid on G1 cell cycle regulatory proteins in various tumors.

Effects of retinoic acid on proliferation, apoptosis, cytotoxicity, migration, and invasion of neuroblastoma cells

BACKGROUND

Because of the known property of less aggressiveness of differentiated cells compared to immatured cells all attempts are made to elucidate whether differentiation inducers possibly could be applied for neuroblastoma therapy. We are interested in examining the influence of retinoic acid (RA) on proliferation, apoptosis, cytotoxicity, migration, and invasion in dependence of the differentiation of neuroblastoma cells classified into N-type (SK-N-FI, SH-SY5Y), I-type (SK-PN-DW), and S-type (SK-N-LO, SK-N-MC) cells.

PROCEDURE

Neuroblastoma cells were exposed to 10(-5) M RA and 200 ng/ml camptothecin (CAM) (control substance for apoptosis). Proliferation, apoptosis, and cytotoxicity were quantified by photometric assays. The influence on migration and invasion of neuroblastoma cells was examined by a scratch-test and by the measurement of the invasion through matrigel coated chamber inserts.

RESULTS

In general, RA treatment induced proliferation inhibition predominantly in the cell lines SK-PN-DW (16%, P < 0.05) and SK-N-MC (8%, (P < 0.001), respectively. In the N-type cell lines SK-N-FI (P > 0.05) and SH-SY5Y (P < 0.001) no proliferation inhibition was determined conforming with no detection of apoptosis. CAM confirmed its capability to induce apoptosis in the cell lines SH-SY5Y (43.6%, P < 0.05), SK-PN-DW (54.8%, P > 0.05), and SK-N-MC (28.9%, P < 0.0 01) except for SK-N-FI with only 9.3% (P > 0.05), but after 24 hr of treatment. Minor signs of restricted migration were observed, while RA treatment reduced significantly the invasion rate through Matrigel of SK-N-FI to 13.3% (P < 0.01), SH-SY5Y to 19.2% (P < 0.05), SK-N-MC to 27.8% (P < 0.05), and SK-N-LO to 17.7% (P < 0.01).

CONCLUSIONS

It is demonstrated that RA treatment can interfere with cell growth and in invasion by inducing neuronal differentiation in N-type and apoptosis in S-type neuroblastoma cell lines.

Vitamin A prevents the irreversible proliferation of vaginal epithelium induced by neonatal injection of keratinocyte growth factor in mice

Exposure of female mice to estrogen during the perinatal period results in estrogen-independent persistent proliferation and cornification of the vaginal epithelium when the animals become adults. However, the occurrence of such irreversible vaginal changes is blocked by concurrent vitamin A treatment. Neonatal exposure to keratinocyte growth factor (KGF), which is a paracrine mediator of epithelial-mesenchymal interactions, also induces the persistent proliferation and cornification of the vaginal epithelium in adult mice. This study was designed to examine whether concurrent administration of vitamin A inhibits the development of the irreversible vaginal changes in mice exposed neonatally to KGF. The vaginal epithelium in ovariectomized 35-day-old mice given 5 microg of KGF for 3 days after birth possessed a significantly larger number of layers and increased thickness as compared to that in control mice. Concurrent injections of 100 IU of vitamin A acetate inhibited the occurrence of the irreversible proliferation of the vaginal epithelium. These changes were equal to the results observed when 20 micro g of estrogen with or without vitamin A acetate was administered for 5 days after birth. Unlike the case of estrogen treatment, the effect of neonatal treatment with KGF seemed to appear after a latent period, since the vaginal epithelium did not show proliferation soon after the treatment. We discuss the inhibitory effect of VA on the irreversible vaginal changes induced by neonatal KGF treatment with reference to endocrine disruption by neonatal estrogen exposure.

The use of retinoids in the prevention and treatment of skin cancer

There has been a significant increase in the number of cases of skin cancer diagnosed in the US in the past few years. Thus, it seems appropriate to review the available compounds that might be used in the chemoprevention of these lesions. This review focuses on the retinoids and details their results in clinical trials for treatment and prevention of skin cancer. Side effects of the various retinoid derivatives are also discussed. It is concluded that isotretinoin (13-cis-retinoic acid) is the most effective retinoid for the prevention of non-melanoma skin cancers in high-risk patients in clinical trials. Current basic research is focused on developing receptor-selective retinoids which would have a higher therapeutic index for the treatment and chemoprevention of skin cancer.