Functional polymorphism in manganese superoxide dismutase and antioxidant status: Their interactions on the risk of cervical intraepithelial neoplasia and cervical cancer

The Role of Selenium and Manganese in the Formation, Diagnosis and Treatment of Cervical, Endometrial and Ovarian Cancer

Selenium (Se) and manganese (Mn) are essential micronutrients that are important elements of cell metabolism. They are involved in the composition of enzyme systems and regulate enzyme activity. Disturbances in the homeostasis of these micronutrients affect the development of many diseases and carcinogenesis, which can be linked to increased levels of oxidative stress and impaired antioxidant properties of many enzymes. Selenium has a very important function in maintaining immune-endocrine, metabolic and cellular homeostasis. Manganese, on the other hand, is important in development, digestion, reproduction, antioxidant defense, energy production, immune response and regulation of neuronal activity. We review the role of selenium and manganese and their effects on tumor growth, metastasis potential and remodeling of the microenvironment. We also describe their role as potential biomarkers in the diagnosis and the potential for the use of Se- and Mn-containing compounds in composition for the treatment of cancer of the reproductive organs.

The structure-function relationships and physiological roles of MnSOD mutants

In this review, we focus on understanding the structure–function relationships of numerous manganese superoxide dismutase (MnSOD) mutants to investigate the role that various amino acids play to maintain enzyme quaternary structure or the active site structure, catalytic potential and metal homeostasis in MnSOD, which is essential to maintain enzyme activity. We also observe how polymorphisms of MnSOD are linked to pathologies and how post-translational modifications affect the antioxidant properties of MnSOD. Understanding how modified forms of MnSOD may act as tumor promoters or suppressors by altering the redox status in the body, ultimately aid in generating novel therapies that exploit the therapeutic potential of mutant MnSODs or pave the way for the development of synthetic SOD mimics.

Effects of folate supplementation on recurrence and metabolic status of cervical intraepithelial neoplasia grade 2/3 in overweight and obese women: a randomized double-blind placebo-controlled trial

BACKGROUND AND OBJECTIVE

Inconsistent evidence showed that folate supplementation may be associated with reduced risk of cancer due to improved metabolic profiles and reduced markers of oxidative stress and inflammation. The aim of this investigation was to quantify the effects of folate supplementation on the recurrence and other metabolic factors of women with cervical intraepithelial neoplasia grade 2/3 (CIN2/3).

METHODS

This randomized, double-blind, placebo-controlled clinical trial was performed among 60 overweight/obese women with CIN2/3. Definitive CIN2/3 confirmation was done via biopsy, pathological diagnosis, as well as colposcopy. Participants were randomly assigned to the intervention group to take 5 mg/day folate supplements or placebo group (n = 30 in each group) for 12 weeks.

RESULTS

The results of the current study showed a non-significant decrease in recurrence of CIN2/3 in the folate group in comparison with the placebo group (3.3% vs. 16.7%, P = 0.08). Compared with the placebo, folate supplementation significantly decreased plasma homocysteine (Hcy) levels (P < 0.001), serum insulin values (in the crude model) (P = 0.01), and homeostasis model assessment of insulin resistance (P = 0.01). Also, folate supplementation resulted in a significant improvement in the quantitative insulin sensitivity check index (P = 0.002) and total antioxidant capacity (P = 0.04) and a significant reduction in high-sensitivity C-reactive protein (P = 0.015) in comparison with the placebo group.

CONCLUSIONS

In conclusion, folate supplementation for 12 weeks among overweight/obese women with CIN2/3 showed a non-significant decrease in its recurrence and had beneficial effects on insulin sensitivity, inflammation, and oxidative stress markers.

Development of cervical intraepithelial lesions and cervical cancer is not influenced by SOD2 RS4880 polymorhism

Some of the more than 200 known HPV types are essential for cervical cancer development, the third type of cancer most incident in the female population. However, for the malignant transformation occur, some cofactors are needed, as the reactive oxygen species (ROS), which can be neutralized by the antioxidant system. The SOD2 enzyme, encoded by the same name gene, is found in mitochondria and is part of the first line of defense against oxidative stress damage. Genetic polymorphisms can act by altering the efficiency of the enzyme, among which the most studied is the rs4880. Thus, the purpose of the present study was to evaluate the association of this polymorphism with HPV infection and the development of low and high grade squamous intraepithelial lesions (LSIL and HSIL) and cervical cancer, in 407 women attended by the public health system in Brazil. HPV detection in cervical secretion samples was carried out by polymerase chain reaction (PCR) and blood samples were used for polymorphism genotyping through PCR followed by restriction fragment length polymorphism (RFLP). PCR and restriction products were subjected to 10% polyacrylamide gel electrophoresis. HPV negative group (control) included 158 women and the HPV positive group (case) 249 women. The infected group was divided into No Lesion (n = 90), LSIL (n = 20), HSIL (n = 67) and cervical cancer (n = 72). The data found on socio-epidemiological characteristics and habits corroborated with data found in the literature. The distribution of genotypes in the control group was 51.9% women TC, 29.8% TT and 18.3% CC. In the case group, the distribution was 55.0% women TC, 26.1% TT and 18.9% CC. This is the first study evaluating the influence of SOD2 rs4880 polymorphism on HPV infection, the development of cervical intraepithelial lesions and cervical cancer in a Brazilian population, although additional studies are needed to corroborate the results.

Unexplored nutritive potential of tomato to combat global malnutrition

Tomato, a widely consumed vegetable crop, offers a real potential to combat human nutritional deficiencies. Tomatoes are rich in micronutrients and other bioactive compounds (including vitamins, carotenoids, and minerals) that are known to be essential or beneficial for human health. This review highlights the current state of the art in the molecular understanding of the nutritional aspects, conventional and molecular breeding efforts, and biofortification studies undertaken to improve the nutritional content and quality of tomato. Transcriptomics and metabolomics studies, which offer a deeper understanding of the molecular regulation of the tomato's nutrients, are discussed. The potential uses of the wastes from the tomato processing industry (i.e., the peels and seed extracts) that are particularly rich in oils and proteins are also discussed. Recent advancements with CRISPR/Cas mediated gene-editing technology provide enormous opportunities to enhance the nutritional content of agricultural produces, including tomatoes. In this regard, genome editing efforts with respect to biofortification in the tomato plant are also discussed. The recent technological advancements and knowledge gaps described herein aim to help explore the unexplored nutritional potential of the tomato.

Nutrigenetics of antioxidant enzymes and micronutrient needs in the context of viral infections

Sustaining adequate nutritional needs of a population is a challenging task in normal times and a priority in times of crisis. There is no 'one-size-fits-all' solution that addresses nutrition. In relevance to the COVID-19 (coronavirus disease 2019) pandemic crisis, viral infections in general and RNA viruses in particular are known to induce and promote oxidative stress, consequently increasing the body's demand for micronutrients, especially those related to antioxidant enzymic systems, thus draining the body of micronutrients, and so hindering the human body's ability to cope optimally with oxidative stress. Common polymorphisms in major antioxidant enzymes, with world population minor allele frequencies ranging from 0·5 to 50 %, are related to altered enzymic function, with substantial potential effects on the body's ability to cope with viral infection-induced oxidative stress. In this review we highlight common SNP of the major antioxidant enzymes relevant to nutritional components in the context of viral infections, namely: superoxide dismutases, glutathione peroxidases and catalase. We delineate functional polymorphisms in several human antioxidant enzymes that require, especially during a viral crisis, adequate and potentially additional nutritional support to cope with the pathological consequences of disease. Thus, in face of the COVID-19 pandemic, nutrition should be tightly monitored and possibly supplemented, with special attention to those carrying common polymorphisms in antioxidant enzymes.

Efficiency comparison of apigenin-7-O-glucoside and trolox in antioxidative stress and anti-inflammatory properties

OBJECTIVES

Chamomile has long been used as a medicinal plant due to its antioxidative and anti-inflammatory activity. Apigenin-7-O-glucoside (AG) is one of the major ethanol extract components from chamomile; however, the underlying mechanism remains unclear.

METHODS

In this study, the antioxidant potential and the anti-inflammatory activities of AG were analysed and compared with those of trolox. We demonstrate the protective effects of AG on free radical-induced oxidative damage of DNA, proteins and erythrocytes. Flow cytometry assay was used to detect ROS production. Additionally, the expression of anti-oxidation-related and inflammation-related factors was detected by ELISA and Western blotting, respectively.

KEY FINDINGS

AG and trolox showed different efficiency as antioxidant in different experimental systems. AG had similar effect as trolox to inhibit H₂ O₂ -induced ROS production in RAW264.7 cells, while exerted stronger inhibition against free radical-induced oxidative damage on erythrocytes than trolox. Interestingly, compared with trolox, AG also had stronger inhibitory effect on LPS-induced NF-κB/NLRP3/caspase-1 signalling in RAW246.7 cells.

CONCLUSIONS

These results suggest the potential of AG as a pharmaceutical drug for anti-oxidation and anti-inflammation, and the combined usage of AG and trolox might promote its efficacy. Our findings will provide new insights into the development of new drugs with antioxidative and anti-inflammatory functions.

The effects of the genetic polymorphisms of antioxidant enzymes on susceptibility to papillary thyroid carcinoma

Several lines of evidences have indicated that inflammation play an important role in the carcinogenesis. During the inflammatory processes, free radical species are produced from oxidative stress. In normal conditions, enzymatic and nonenzymatic antioxidants remove these products. Manganese superoxide dismutase (MnSOD), glutathione peroxidase-1 (GPx-1), and catalase (CAT) are three important enzymes. Therefore, this study aimed to evaluate the effects of MnSOD (SOD2), GPX-1, and CAT genetic polymorphisms on papillary thyroid carcinoma (PTC) susceptibility. A total of 134 patients with PTC and 151 healthy controls were recruited to participate in this study. All samples were genotyped for SOD2 rs4880, GPX1 1050450, and CAT rs7943316 polymorphisms by polymerase chain reaction-restriction fragment length polymorphism method. The frequencies of the rs1050450, rs4880, and rs7943316 alleles and genotypes were not different between PTC patients and controls. However, the TC genotype of SOD2 rs4880 polymorphism was significantly higher in males compared to that in females in PTC patients (odds ratio [OR], 3.9 [95% CI, 1.5-11], p = .007). The rs4880 polymorphism was also associated with higher stages (III-IV) of PTC in dominant model. No significant correlation was found between GPX1-rs1050450 and CAT-rs7943316 polymorphisms and demographic, clinical, and pathological features of the disease. The SOD2 rs4880CT genotype was more frequent in males with PTC and patients with higher stages (III-IV) of disease (OR, 2.9 [95% CI, 1.1-7.7], p = .04). However, no significant association was found between GPX1-rs1050450 and CAT-rs7943316 variants and PTC or its demographic, clinical, and pathological features.

Association between SOD2 V16A variant and urological cancer risk

Background: The correlation between superoxide dismutase 2 (SOD2) V16A variant and urological cancer susceptibility has been widely studied, however, with divergent results.

Results: Totally, 9,910 cancer patients and 11,239 control subjects were enrolled. V16A variant is associated with an increased susceptibility to urological cancer (A-allele vs. V-allele: OR = 1.06, 95% CI = 1.00 – 1.13, P = 0.047; AA+AV vs. VV: OR = 1.09, 95% CI = 1.02 – 1.16, P = 0.008), especially for prostate cancer (PCa). Serum SOD2 level of PCa patients with VV+VA genotypes was lower than in those with AA genotypes. SOD2 expression is downregulated in both prostate and bladder cancer, as compared to the control. Furthermore, SOD2 was found to be downregulated in more advanced PCa participants, as compared to the ones in early stages. PCa subjects with low SOD2 expression displayed a shorter disease-free survival (DFS) time compared to that of the high SOD2 expression counterparts.

Conclusions: The SOD2 V16A variant may be associated with increased urological cancer susceptibility, especially for prostate cancer.

Methods: A pooled analysis utilizing odds ratios (ORs), in silico tools and ELISA was adopted to demonstrate this association. We also used immunohistochemical staining (IHS) to assess SOD2 expression.

Bioavailability of Fat-Soluble Vitamins and Phytochemicals in Humans: Effects of Genetic Variation

Recent data have shown that interindividual variability in the bioavailability of vitamins A (β-carotene), D, and E, and carotenoids (lutein and lycopene), as well as that of phytosterols, is modulated by single nucleotide polymorphisms (SNPs). The identified SNPs are in or near genes involved in intestinal uptake or efflux of these compounds, as well as in genes involved in their metabolism and transport. The phenotypic effect of each SNP is usually low, but combinations of SNPs can explain a significant part of the variability. Nevertheless, results from these studies should be considered preliminary since they have not been validated in other cohorts. Guidelines for future studies are provided to ensure that sound associations are elucidated that can be used to build consolidated genetic scores that may allow recommended dietary allowances to be tailored to individuals or groups by taking into account the multiloci genotypic signature of people of different ethnic origin or even of individuals.

Oxidative stress in cervical cancer pathogenesis and resistance to therapy

Cervical cancer (CC) is one of the most common cancers among females, and it is most notable in developing countries. The exact etiology of CC is poorly understood; but, smoking, oral contraceptives, immunosuppression, and infection with human papillomavirus (HPV) may increase the risk of CC. There is also an association between CC and oxidative stress. Oxidative stress is caused by a disturbed oxidant-antioxidant balance in favor of the former, leading to an excessive generation of free radicals, particularly reactive oxygen species (ROS), and subsequently to biological damages. Thus, redox enzymatic and nonenzymatic regulators are required to maintain the redox homeostasis. Dysregulated antioxidants system and the pathogenic role of oxidative stress in CC have been investigated in several clinical and preclinical studies. In this study, we reviewed studies that have addressed the cross-talk between oxidative stress and CC pathogenesis and resistance to therapy.

Genetic factors involved in the bioavailability of tomato carotenoids

PURPOSE OF REVIEW

To provide an update on the genetic factors recently associated with the interindividual variability of tomato carotenoid bioavailability.

RECENT FINDINGS

Several clinical studies have demonstrated that the main carotenoids found in tomatoes (lycopene, phytoene, phytofluene, β-carotene, lutein) all display relatively large interindividual variabilities of their bioavailability, with coefficients of variations more than 70%. The bioavailability of the parent molecules, and the blood/tissue appearance of their metabolites, is modulated by numerous proteins, involved in intestinal absorption and metabolism, blood lipoprotein transport or tissue uptake. Several single nucleotide polymorphisms (SNPs) have been associated with the interindividual variability of lycopene, lutein and β-carotene bioavailability, with six genes consistently shared between the three carotenoids, and in particular one SNP in ELOVL fatty acid elongase 2. The effects of the genetic variants taken separately are relatively low, that is each variant is usually associated with only a few percentage of the variability but multivariate analyses suggest that the additive effect of several genetic variants can explain a significant fraction of tomato carotenoid bioavailability.

SUMMARY

Additional studies are needed to improve our knowledge of the genetic determinants of tomato carotenoid bioavailability but progress in this field could one day allow nutritionists to provide more personalized dietary recommendations.

Association between MnSOD Val16Ala Polymorphism and Cancer Risk: Evidence from 33,098 Cases and 37,831 Controls

Manganese superoxide dismutase (MnSOD) plays a critical role in the defense against reactive oxygen species. The association between MnSOD Val16Ala polymorphism and cancer risk has been widely studied, but the results are contradictory. To obtain more precision on the association, we performed the current meta-analysis with 33,098 cases and 37,831 controls from 88 studies retrieved from PubMed, Embase, Chinese National Knowledge Infrastructure (CNKI), and Wanfang databases. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of association. We found that the polymorphism was associated with an increased overall cancer risk (homozygous: OR = 1.09, 95% CI = 1.00-1.19; heterozygous: OR = 1.07, 95% CI = 1.02-1.12; dominant: OR = 1.08, 95% CI = 1.02-1.14; and allele comparison: OR = 1.06, 95% CI = 1.02-1.11). Stratification analysis further showed an increased risk for prostate cancer, Asians, Caucasians, population-based studies, hospital-based studies, low quality and high quality studies. However, the increased risk for MnSOD Val16Ala polymorphism among Asians needs further validation based on the false-positive report probability (FPRP) test. To summarize, this meta-analysis suggests that the MnSOD Val16Ala polymorphism is associated with significantly increased cancer risk, which needs further validation in single large studies.

The relationship between MnSOD Val16Ala gene polymorphism and the level of serum total antioxidant capacity with the risk of chronic kidney disease in type 2 diabetic patients: a nested case-control study in the Tehran lipid glucose study

Background

Several studies have shown significant associations between manganese superoxide dismutase (MnSOD) Val16Ala polymorphism and diabetic complications, but this association has not been explored in relation with chronic kidney disease (CKD) in Type 2 diabetes mellitus (T2DM) patients. Total antioxidant capacity (TAC) level changes in diabetic condition and may play important role in onset or progression of the disease and its complications. The present study investigated the association of MnSOD Val16Ala polymorphism and serum TAC with the risk of CKD in T2DM patients.

Methods

This nested case-control study included 280 type 2 diabetic patients with CKD and 280 age, sex and diabetes duration-matched control subjects selected from the participants of the Tehran Lipid and Glucose Study. MnSOD val16Ala (rs4880) SNP was genotyped by the Tetra-Primer ARMS-polymerase chain reaction analysis. Serum TAC was measured using ferric-reducing antioxidant power assay. Statistical analysis was performed using STATA statistical package v.12.0 or SPSS (Version 22.0).

Results

The Ala allele of the MnSOD Val16Ala polymorphism was associated with a lower risk of CKD (odds ratio (OR), 0.55; 95% confidence interval (CI), 0.36–0.84; P = 0.006). Median serum TAC in CKD group was 920 μmol/L and was significantly lower (p < 0.001) compared to the control group (1045 μmol/L). Using an adjusted conditional logistic regression, we didn’t observe any significant interaction between MnSOD Val16Ala SNP with quartiles of serum TAC in relation to CKD.

Conclusion

A significant association was found between the MnSOD Val16Ala polymorphism and CKD, but this association is not affected by serum TAC level in T2DM patients.

Association of MnSOD AA Genotype with the Progression of Prostate Cancer

Purpose

To investigate whether manganese superoxide dismutase (MnSOD) genetic polymorphism is associated with the clinical significance of prostate cancer.

Materials and Methods

Prostates were obtained from 194 deceased men 45 years or older who did not have a history of prostate cancer. Serial sections and histological examinations of the prostate were performed. The MnSOD genotypes of the specimens were determined by polymerase chain reaction restriction fragment length polymorphism analysis.

Results

Of the 194 men, 31 and 26 had clinically insignificant and significant prostate cancer. Clinically significant cancer comprised 29% and 58% of the cancers in men <70 and >70 years old, respectively. The age-specific proportion of significant cancer significantly increased with the advance of age (p<0.001). MnSOD AA, as compared with the other genotypes (VA and VV together), was associated with significant prostate cancer across all ages, odds ratio (OR) 2.34, 95% confidence interval (CI) 0.99-5.49, and in men older than 69 years (OR 4.89, 95% CI 1.51-15.8), but not in men younger than 70 years. The genotype was not associated with clinically insignificant cancer regardless of age. The comparison between significant and insignificant cancer, the OR (95% CI) for MnSOD AA was 5.04 (1.05-24.2) (sensitivity 0.57, specificity 0.78, positive predictive value 0.78) in men older than 69 years.

Conclusions

MnSOD polymorphism is strongly associated with the clinical significance of prostate cancer in men older than 69 years, but not in men younger than 70 years suggesting that oxidative stress may be involved in the progression of the disease. MnSOD may be a clinically useful marker to predict the potential of progression of prostate cancer.

Premenopausal plasma carotenoids, fluorescent oxidation products, and subsequent breast cancer risk in the nurses' health studies

High levels of circulating carotenoids are hypothesized to reduce breast cancer risk, potentially due to their antioxidant properties. However, little is known about the relationship between carotenoid exposure earlier in life and risk. We examined associations of premenopausal plasma carotenoids and markers of oxidative stress and risk of breast cancer among 1179 case-control pairs in the Nurses' Health Study (NHS) and NHSII. Levels of α- and β-carotene, β-cryptoxanthin, lycopene, and lutein/zeaxanthin were quantified by high-performance liquid chromatography. Three fluorescent oxidation products (FlOP_360, FlOP_320, FlOP_400) were measured in a subset of participants by spectrofluoroscopy. Multivariate conditional logistic regression was used to estimate odds ratios and 95 % confidence intervals for breast cancer by quartile, as well as P values for tests of linear trend. We additionally examined whether 45 single-nucleotide polymorphisms (SNPs) in five genes involved in oxidative and antioxidative processes or carotenoid availability were associated with risk. Carotenoid measures were not inversely associated with breast cancer risk. No differences by estrogen receptor status were observed, though some inverse associations were observed among women postmenopausal at diagnosis. Plasma FlOP levels were not positively associated with risk, and suggestive inverse associations with FlOP_320 and FlOP_360 were observed. Several SNPs were associated with carotenoid levels, and a small number were suggestively associated with breast cancer risk. We observed evidence of interactions between some SNPs and carotenoid levels on risk. We did not observe consistent associations between circulating levels of premenopausal carotenoids or FlOP levels and breast cancer risk.

The MnSOD Ala16Val SNP: relevance to human diseases and interaction with environmental factors

The relevance of reactive oxygen species (ROS) production relies on the dual role shown by these molecules in aerobes. ROS are known to modulate several physiological phenomena, such as immune response and cell growth and differentiation; on the other hand, uncontrolled ROS production may cause important tissue and cell damage, such as deoxyribonucleic acid oxidation, lipid peroxidation, and protein carbonylation. The manganese superoxide dismutase (MnSOD) antioxidant enzyme affords the major defense against ROS within the mitochondria, which is considered the main ROS production locus in aerobes. Structural and/or functional single nucleotide polymorphisms (SNP) within the MnSOD encoding gene may be relevant for ROS detoxification. Specifically, the MnSOD Ala16Val SNP has been shown to alter the enzyme localization and mitochondrial transportation, affecting the redox status balance. Oxidative stress may contribute to the development of type 2 diabetes, cardiovascular diseases, various inflammatory conditions, or cancer. The Ala16Val MnSOD SNP has been associated with these and other chronic diseases; however, inconsistent findings between studies have made difficult drawing definitive conclusions. Environmental factors, such as dietary antioxidant intake and exercise have been shown to affect ROS metabolism through antioxidant enzyme regulation and may contribute to explain inconsistencies in the literature. Nevertheless, whether environmental factors may be associated to the Ala16Val genotypes in human diseases still needs to be clarified.

Different association of manganese superoxide dismutase gene polymorphisms with risk of prostate, esophageal, and lung cancers: evidence from a meta-analysis of 20,025 subjects

Altered expression or function of manganese superoxide dismutase (MnSOD) has been shown to be associated with cancer risk but assessment of gene polymorphisms has resulted in inconclusive data. Here a search of published data was made and 22 studies were recruited, covering 20,025 case and control subjects, for meta- analyses of the association of MnSOD polymorphisms with the risk of prostate, esophageal, and lung cancers. The data on 12 studies of prostate cancer (including 4,182 cases and 6,885 controls) showed a statistically significant association with the risk of development in co-dominant models and dominant models, but not in the recessive model. Subgroup analysis showed there was no statistically significant association of MnSOD polymorphisms with aggressive or nonaggressive prostate cancer in different genetic models. In addition, the data on four studies of esophageal cancer containing 620 cases and 909 controls showed a statistically significant association between MnSOD polymorphisms and risk in all comparison models. In contrast, the data on six studies of lung cancer with 3,375 cases and 4,050 controls showed that MnSOD polymorphisms were significantly associated with the decreased risk of lung cancer in the homozygote and dominant models, but not the heterozygote model. A subgroup analysis of the combination of MnSOD polymorphisms with tobacco smokers did not show any significant association with lung cancer risk, histological type, or clinical stage of lung cancer. The data from the current study indicated that the Ala allele MnSOD polymorphism is associated with increased risk of prostate and esophageal cancers, but with decreased risk of lung cancer. The underlying molecular mechanisms warrant further investigation.

Zeaxanthin Induces Apoptosis in Human Uveal Melanoma Cells through Bcl-2 Family Proteins and Intrinsic Apoptosis Pathway

The cytotoxic effects of zeaxanthin on two human uveal melanoma cell lines (SP6.5 and C918) and related signaling pathways were studied and compared to effects on normal ocular cells (uveal melanocytes, retinal pigment epithelial cells, and scleral fibroblasts). MTT assay revealed that zeaxanthin reduced the cell viability of melanoma cells in a dose-dependent manner (10, 30, and 100 μM), with IC₅₀ at 40.8 and 28.7 μM in SP6.5 and C918 cell lines, respectively. Zeaxanthin did not affect the viability of normal ocular cells even at the highest levels tested (300 μM), suggesting that zeaxanthin has a selectively cytotoxic effect on melanoma cells. Zeaxanthin induced apoptosis in melanoma cells as indicated by annexin V and ethidium III flow cytometry. Western blot analysis demonstrated that zeaxanthin decreased the expression of antiapoptotic proteins (Bcl-2 and Bcl-xL) and increased the expression of proapoptotic proteins (Bak and Bax) in zeaxanthin-treated melanoma cells. Zeaxanthin increased mitochondrial permeability as determined by JC-1 fluorescein study. Zeaxanthin also increased the level of cytosol cytochrome c and caspase-9 and -3 activities, but not caspase-8, as measured by ELISA assay or colorimetric assay. All of these findings indicate that the intrinsic (mitochondrial) pathway is involved in zeaxanthin-induced apoptosis in uveal melanoma cells.

Single nucleotide polymorphisms in DNA repair genes and risk of cervical cancer: A case-control study

In this report, we describe a case control study in a Chinese population aimed at identifying possible associations between susceptibility to cervical cancer and single nucleotide polymorphisms in XRCC1 194C>T, XRCC1 280G>A, XRCC1 399G>A, ERCC2 751A>C, ERCC2 156C>A, ERCC1 118C>T, PARP1 762T>C, RAD51 135G>C and HER2 655A>G. The cases comprised 154 patients: 80 cervical squamous cell carcinomas (SCCs), 2 adenocarcinomas and 72 cervical intraepithelial neoplasias (CINs). A total of 177 healthy women were recruited as the controls. A significant association was found between ERCC1 118C>T and SCC in the additive genetic model [odds ratio (OR)=1.711; 95% confidence interval (CI), 1.089-2.880; p=0.021] and the dominant genetic model (OR=1.947; 95% CI, 1.056-3.590; p=0.033). Among women with a smoking family member, ERCC1 118C>T increased SCC risk in the additive model (OR=2.800; 95% CI, 1.314-5.968; p=0.008). For women who had first intercourse before 22 years of age, XRCC1 280G>A was found to act as a protective factor for SCC under the additive model (OR=0.228; 95% CI, 0.058-0.900; p=0.035), while RAD51 135G>C was a risk factor for CIN (OR=4.246; 95% CI, 1.335-13.502; p=0.014). For women who had first intercourse after 22 years of age, the additive genetic model showed RAD51 135G>C (OR=0.359; 95% CI, 0.138-0.934; p=0.036) and HER2 655A>G (OR=0.309; 95% CI, 0.098-0.972; p=0.045) to be protective factors for SCC. XRCC1 399G>A increased CIN risk among women who first gave birth before the age of 22 in the additive genetic model (OR=4.459; 95% CI, 1.139-17.453; p=0.032). For those who first gave birth after age 22, ERCC1 118C>T was found to be a risk factor for SCC in the additive genetic model (OR=1.884; 95% CI, 1.088-3.264; p=0.024). A significant interaction was observed between RAD51 135G>C and age at first intercourse (p(interaction)=0.033 for SCC, p(interaction)=0.021 for CIN), as well with sexual partner number (p(interaction)=0.001 for SCC). The interaction between HER2 655A>G and age at first intercourse, ERCC2 156C>A and family smoking status and XRCC1 280G>A and alcohol consumption were significant, with p(interaction)=0.023 for SCC, p(interaction)=0.021 for CIN and p(interaction)=0.025 for SCC, respectively.