Potential anticancer effect of sodium caprate on human gastric cancer cells.

The role of sodium caprate (C10) in enhancing drug absorption is well established; however, little information is available on its role as an anticancer drug. This study aimed to evaluate the anticancer effect of C10 in gastric cancer cells. The mechanism of cytotoxicity of C10 was evaluated by western blotting following treatment of the gastric cancer cells with various concentrations of C10. C10 cytotoxicity was measured via MTS (3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H tetrazolium), lactate dehydrogenase (LDH), cAMP, and ATP assays. Gastric cancer cells were observed by electron microscopy following treatment with C10. Then, xenograft mice that were inoculated with gastric cancer cells were treated with C10 for 4 weeks, after which the changes in tumor size were measured. C10 triggered apoptosis in the gastric cancer cells through the mitochondrial pathway at concentrations of more than 0.2 mM. However, 15 mM of C10 induced necrosis in gastric cancer cells by causing cellular swelling and the formation of holes in the cell membrane. Levels of cAMP and ATP decreased significantly following exposure to 15 mM C10 for 1 h. Additionally, the size of the xenograft tumors was significantly reduced by 24% after 4 weeks of C10 treatment (p < 0.05). This study indicates that C10 induces apoptosis and necrosis in a concentration-dependent manner and has clear anticancer effects on gastric cancer cells.

No association between maternal and child PFAS concentrations and repeated measures of ADHD symptoms at age 2½ and 5 years in children from the Odense Child Cohort.

INTRODUCTION: The potential impact of exposure to perfluoroalkyl substances (PFAS) on childhood Attention-Deficit Hyperactivity-Disorder (ADHD) is unclear and deserves scrutiny. The majority of previously conducted longitudinal studies found no association between maternal serum-PFAS concentrations and ADHD symptoms in the offspring, but some studies observed possible associations with postnatal PFAS exposures, mainly in girls. OBJECTIVE: To investigate the association between maternal and child serum concentrations of five PFAS and symptoms of ADHD at ages 2½ and 5 years. METHODS: In the Odense Child Cohort (OCC) women were recruited in early pregnancy in 2010-12 and their children are being prospectively followed. Mothers donated serum samples in the first trimester and children at age 18 months to be analyzed for perfluorohexane sulfonic acid (PFHxS), perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA). Parents completed the Child Behavior Check List for ages 1.5-5 years (CBCL/1½-5), including a 6-item ADHD symptom scale at age 2½ years and again at 5 years. Negative binomial and logistic regression models taking account of repeated measures were used to investigate the association between maternal and child serum-PFAS concentrations and the ADHD symptom score. Effect modification by child sex was investigated as well. RESULTS: A total of 1138 mother-child pairs were included. At age 2½ years, 17.4% of the children had an ADHD scale score ≥ 5 (equivalent to the 90th percentile), whereas the proportion was 15.8% at age 5. We found no association between either maternal or child PFAS concentrations in serum and symptoms of ADHD at age 2½ or 5 years, and no evidence of effect modification by sex. CONCLUSION: We found no evidence of an association between early-life PFAS exposure and the risk of developing symptoms of ADHD.

Perfluorodecanoic acid induces meiotic defects and deterioration of mice oocytes in vitro.

Perfluorodecanoic acid (PFDA) is a member of the perfluoroalkyl substances, which are toxic to organic functions. Recently, it has been found in follicular fluid, seriously interfering with reproduction. Follicular fluid provides the oocyte with necessary resources during the process of oocytes maturation. However, the effects of PFDA on the oocyte need investigation. Our study evaluated the impacts of PFDA on the meiosis and development potential of mouse oocytes by exposing oocytes to PFDA in vitro at 350, 400, and 450 µM concentrations. The results showed that exposure to PFDA resulted in the first meiotic prophase arrest by obstructing the function of the maturation-promoting factor. It also induced the dysfunction of the spindle assembly checkpoint, expedited the progression of the first meiotic process, and increased the risk of aneuploidy. The oocytes treated with PFDA had a broken cytoskeleton which also contributed to meiotic maturation failure. Besides, PFDA exposure caused mitochondria defections, increased the reactive oxygen species level in oocytes, and consequently induced oocyte apoptosis. Moreover, PFDA produced epigenetic modifications in oocytes and increased the frequency of mature oocytes with declined development potential. In summary, our data indicated that PFDA disturbs the meiotic process and induces oocyte quality deterioration.

Safety assessment of cosmetics by read across applied to metabolomics data of in vitro skin and liver models.

As a result of the cosmetics testing ban, safety evaluations of cosmetics ingredients must now be conducted using animal-free methods. A common approach is read across, which is mainly based on structural similarities but can also be conducted using biological endpoints. Here, metabolomics was used to assess biological effects to enable a read across between a candidate cosmetic ingredient, DIV665, only studied using in vitro assays, and a structurally similar reference compound, PA102, previously investigated using traditional in vivo toxicity methods. The (1) cutaneous distribution after topical application, (2) skin metabolism, (3) liver metabolism and (4) effect on the intracellular metabolomic profiles of in vitro skin and hepatic models, SkinEthic®RHE model and HepaRG® cells were investigated. The compounds exhibited similar skin penetration and skin and liver metabolism, with small differences attributed to their physicochemical properties. The effects of both compounds on the metabolome of RHE and HepaRG® cells were similarly small, both in terms of the metabolites modulated and the magnitude of changes. The patterns of metabolome changes did not fit with any known signature relating to a mode of action known to be linked to liver toxicity e.g. modification of the Krebs cycle, urea synthesis and lipid metabolism, were more reflective of transient adaptive responses. Overall, these studies indicate that PA102 is biologically similar to DIV665, allowing read across of safety endpoints, such as in vivo sub-chronic (but not reproduction toxicity) studies, for the former to be applied to DIV665. Based on this, in the absence of animal data (which is prohibited for new chemicals), it could be concluded that DIV665 applied according to the consumer topical use scenario, is similar to PA102, and is predicted to exhibit low local skin and systemic toxicity.

Maternal exposure to perfluoroalkyl chemicals and anogenital distance in the offspring: A Faroese cohort study.

Exposure to perfluoroalkyl substances (PFASs) has in some studies been associated with reduced anogenital distance (AGD) in newborns as a sensitive indicator of prenatal anti-androgenic exposure. The aim of this study was to investigate the association between maternal PFAS exposure and offspring AGD in a population with wide ranges of PFAS exposures. Participants were recruited in the Faroe Islands in 2007-2009, and information on AGD and PFAS exposure was obtained from 463 mother-infant pairs. Perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were measured in maternal serum. Data were analyzed using multiple linear regression analysis adjusted for birth weight, child age at examination, parity, and maternal education level. Among boys, higher maternal serum concentrations of PFOA, PFOS, PFNA and PFDA were significantly associated with a longer AGD, both with the exposure entered as a continuous variable and as quartiles. Boys in the highest quartile of PFOA, PFOS, PFNA and PFDA exposure had an increase in AGD of 1.2 mm (95 % CI 0.1;2.2), 1.3 mm (95 % CI 0.3;2.3), 1.0 mm (95 % CI 0.0:2.0) and 1.3 mm (95 % CI 0.3;2.4), respectively, when compared to boys in the lowest quartile of exposure (p < 0.05). No significant association was found between male AGD and PFHxS. No association was found for girls. In conclusion, elevated maternal exposure to major PFASs was significantly associated with a longer AGD in boys. No significant associations were found among girls, thus suggesting a sex-dimorphic effect of PFAS exposure.

Life-course Exposure to Perfluoroalkyl Substances in Relation to Markers of Glucose Homeostasis in Early Adulthood.

OBJECTIVE: To investigate the prospective associations of life-course perfluoroalkyl substances (PFASs) exposure with glucose homeostasis at adulthood. METHODS: We calculated insulin sensitivity and beta-cell function indices based on 2-h oral glucose tolerance tests at age 28 in 699 Faroese born in 1986-1987. Five major PFASs were measured in cord whole blood and in serum from ages 7, 14, 22, and 28 years. We evaluated the associations with glucose homeostasis measures by PFAS exposures at different ages using multiple informant models fitting generalized estimating equations and by life-course PFAS exposures using structural equation models. RESULTS: Associations were stronger for perfluorooctane sulfonate (PFOS) and suggested decreased insulin sensitivity and increased beta-cell function-for example, ß (95% CI) for log-insulinogenic index per PFOS doubling = 0.12 (0.02, 0.22) for prenatal exposures, 0.04 (-0.10, 0.19) at age 7, 0.07 (-0.07, 0.21) at age 14, 0.05 (-0.04, 0.15) at age 22, and 0.04 (-0.03, 0.11) at age 28. Associations were consistent across ages (P for age interaction > 0.10 for all PFASs) and sex (P for sex interaction > 0.10 for all PFASs, except perfluorodecanoic acid). The overall life-course PFOS exposure was also associated with altered glucose homeostasis (P = 0.04). Associations for other life-course PFAS exposures were nonsignificant. CONCLUSIONS: Life-course PFAS exposure is associated with decreased insulin sensitivity and increased pancreatic beta-cell function in young adults.

RIFM fragrance ingredient safety assessment, 5- and 6-decenoic acid, CAS Registry Number 72881-27-7.

The existing information supports the use of this material as described in this safety assessment. 5- and 6-Decenoic acid was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data from read-across analog oleic acid (CAS # 112-80-1) show that 5- and 6-decenoic acid is not expected to be genotoxic. The repeated dose, reproductive, and local respiratory toxicity endpoints were evaluated using the threshold of toxicological concern (TTC) for a Cramer Class I material, and the exposure to 5- and 6-decenoic acid is below the TTC (0.03 mg/kg/day, 0.03 mg/kg/day, and 1.4 mg/day, respectively). The skin sensitization endpoint was completed using the dermal sensitization threshold (DST) for non-reactive materials (900 µg/cm2); exposure is below the DST. The phototoxicity/photoallergenicity endpoints were evaluated based on ultraviolet/visible (UV/Vis) spectra; 5- and 6-decenoic acid is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated; 5- and 6-decenoic acid was found not to be persistent, bioaccumulative, and toxic (PBT) as per the International Fragrance Association (IFRA) Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., Predicted Environmental Concentration/Predicted No Effect Concentration [PEC/PNEC]), are <1.

Perfluoroalkyl acids and their isomers, diabetes, anemia, and albuminuria: Variabilities with deteriorating kidney function.

Data for US adults aged ≥20 years from National Health and Nutrition Examination Survey for the years 2003-2014 were analyzed to evaluate how adjusted (N = 8481) and unadjusted (N = 9080) levels of selected perfluoroalkyl acids (PFAA) vary across the different stages of glomerular function (GF) among those who did not have diabetes, anemia, or albuminuria as compared to those who had diabetes only, anemia only, and albuminuria only. PFAAs selected for analyses were: perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorodecanoic acid (PFDA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA). Irrespective of GF stage, there was no noticeable evidence to suggest that adjusted levels of PFAA for those with diabetes only are any lower than those with no diabetes, no anemia, and no albuminuria. Those who had anemia only were found to have lower adjusted levels of at least PFOA, PFOS, PFDA, and PFHxS than those who had no diabetes, no anemia, and no albuminuria. These results were seen in the presence (eGFR < 60 mL/min/1.73 m2) as well as the absence of chronic kidney disease. For GF-1 (eGFR > 90 mL/min/1.73 m2), GF-2 (60 ≤ eGFR ≤ 90 mL/min/1.73 m2), and GF-3B/4 (15 < eGFR ≤ 45 mL/min/1.73 m2), those who had albuminuria only had lower adjusted levels of PFOA, PFOS, and PFHxS than those who had no diabetes, no anemia, and no albuminuria. In general, adjusted levels of those who had albuminuria only were lower than those who had anemia only at GF-3 and more often than not at GF-1 and GF-2. Rise in adjusted levels of PFAA from GF-1 to GF-3A (45 < eGFR < 60 mL/min/1.73 m2) was faster for those with anemia only than any other comparison group for the total population and females.

Thyroid disrupting effects of perfluoroundecanoic acid and perfluorotridecanoic acid in zebrafish (Danio rerio) and rat pituitary (GH3) cell line.

Due to global restriction on perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), the use of long-chain perfluoroalkyl substances (PFASs, C > 8) and their environmental occurrences have increased. PFOS and PFOA have been known for thyroid disruption, however, knowledge is still limited on thyroid disrupting effects of long-chain PFASs (C > 10). In this study, two long-chain perfluorinated carboxylic acids (PFCAs), i.e., perfluoroundecanoic acid (PFUnDA) and perfluorotridecanoic acid (PFTrDA), were chosen and investigated for thyroid disrupting effects, using zebrafish embryo/larvae and rat pituitary cell line (GH3). For comparison, PFOA was also added as a test chemical and also investigated for its thyroid disruption potential. Following a 5 d exposure to PFTrDA, zebrafish larvae showed upregulation of the genes responsible for thyroid hormone synthesis (tshß, nkx2.1, nis, tpo, mct8) and (de)activation (dio1, dio2). In contrast, both PFUnDA and PFOA induced no regulatory changes except for upregulation of a thyroid metabolism related gene (ugt1ab). Morphological changes such as decreased eyeball size, increased yolk sac size, or deflated swim bladder, occurred following exposure to PFUnDA, PFTrDA, and PFOA. In GH3 cells, exposure to PFUnDA and PFTrDA upregulated Tshß gene, suggesting that these PFCAs increase thyroid hormone synthesis through stimulation by Tsh. In summary, both long-chain PFCAs could cause transcriptional changes of thyroid regulating genes that may lead to increased malformation of the zebrafish larvae, but the pathway of thyroid disruption appears to be different by the chain length. Confirmation and validation in adult fish following long term exposure are warranted.

RIFM fragrance ingredient safety assessment, decanoic acid, CAS Registry Number 334-48-5.

The existing information supports the use of this material as described in this safety assessment. Decanoic acid was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data on the target material and from read-across analog nonanoic acid (CAS # 112-05-0) show that decanoic acid is not expected to be genotoxic. Data on read-across analog octanoic acid (CAS # 124-07-2) provide a calculated MOE >100 for the repeated dose and reproductive toxicity endpoints. Based on the existing data, decanoic acid does not present a concern for skin sensitization under the current, declared levels of use. The phototoxicity/photoallergenicity endpoints were evaluated based on UV spectra; decanoic acid is not expected to be phototoxic/photoallergenic. The local respiratory toxicity endpoint was evaluated using the TTC for a Cramer Class I material, and the exposure to decanoic acid is below the TTC (1.4 mg/day). The environmental endpoints were evaluated; decanoic acid was found not to be PBT as per the IFRA Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., PEC/PNEC), are <1.

Regulation of Hox and ParaHox genes by perfluorochemicals in mouse liver.

Homeobox (Hox) genes encode homeodomain proteins, which play important roles in the development and morphological diversification of organisms including plants and animals. Perfluorinated chemicals (PFCs), which are well recognized industrial pollutants and universally detected in human and wildlife, interfere with animal development. In addition, PFCs produce a number of hepatic adverse effects, such as hepatomegaly and dyslipidemia. Homeodomain proteins profoundly contribute to liver regeneration. Hox genes serve as either oncogenes or tumor suppressor genes during target organ carcinogenesis. However, to date, no study investigated whether PFCs regulate expression of Hox genes. This study was designed to determine the regulation of Hox (including Hox-a to -d subfamily members) and paraHox [including GS homeobox (Gsx), pancreatic and duodenal homeobox (Pdx), and caudal-related homeobox (Cdx) family members] genes by PFCs including perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) in mouse liver. 46.4 mg/kg PFNA induced mRNA expression of Hoxa5, b7, c5, d10 and Pdx1 in wild-type and CAR-null mouse livers, but not in PPARα-null mouse livers, indicating a PPARα-dependent manner. PFOA, PFNA, and PFDA all induced mRNA expression of Hoxa5, b7, c5, d10, Pdx1 and Zeb2 in wild-type but not PPARα-null mouse livers. In addition, in Nrf2-null mouse livers, PFNA continued to increase mRNA expression of Hoxa5 and Pdx1, but not Hoxb7, c5 or d10. Furthermore, Wy14643, a classical PPARα agonist, induced mRNA expression of Hoxb7 and c5 in wild-type but not PPARα-null mouse livers. However, Wy14643 did not induce mRNA expression of Hoxa5, d10 or Pdx1 in either wild-type or PPARα-null mouse livers. TCPOBOP, a classical mouse CAR agonist, increased mRNA expression of Hoxb7, c5 and d10 but not Hoxa5 or Pdx1 in mouse livers. Moreover, PFNA decreased cytoplasmic and nuclear Hoxb7 protein levels in mouse livers. However, PFNA increased cytoplasmic Hoxc5 protein level but decreased nuclear Hoxc5 protein level in mouse livers. In conclusion, PFCs induced mRNA expression of several Hox genes such as Hoxb7, c5 and d10, mostly through the activation of PPARα and/or Nrf2 signaling.

Cytotoxicity of perfluorodecanoic acid on mouse primary nephrocytes through oxidative stress: Combined analysis at cellular and molecular levels.

Long-chain perfluoroalkyl acids (PFAAs) such as perfluorodecanoic acid (PFDA) are toxic, persistent organic pollutants. This study investigated the harmful effect of PFDA on mouse primary nephrocytes and its mechanism at cellular and molecular levels. Cellular results showed that PFDA exhibited nephrotoxicity with decreased cell viability and increased apoptosis. The increase of intracellular reactive oxygen species (ROS) content and the decrease of intracellular superoxide dismutase (SOD) activity were significant (p < 0.01) when PFDA concentration exceeded 10 µM. Additionally, the molecular results indicated that PFDA bind with Val-A98 in the surface of Cu/Zn-SOD by a 3.11 Šhydrogen bond driven by Van der Waals' force and hydrogen bonding force, which triggered the structural changes and decreased activity of Cu/Zn-SOD. Altogether, the intracellular oxidative stress is the main driver of nephrocyte apoptosis; and the interaction of PFDA and Cu/Zn-SOD exacerbated the oxidative stress in nephrocytes, which is also a nonnegligible reason of cytotoxicity induced by PDFA. This study represented a meaningful method to explore the toxic effect and mechanism of xenobiotics at cellular and molecular levels. The findings have implications for revealing the clearance of long-chain PFAAs in vivo.

Prenatal exposure to perfluorodecanoic acid is associated with lower circulating concentration of adrenal steroid metabolites during mini puberty in human female infants. The Odense Child Cohort.

BACKGROUND: Fetal programming of the endocrine system may be affected by exposure to perfluoroalkyl substances (PFAAs), as they easily cross the placental barrier. In vitro studies suggest that PFAAs may disrupt steroidogenesis. "Mini puberty" refers to a transient surge in circulating androgens, androgen precursors, and gonadotropins in infant girls and boys within the first postnatal months. We hypothesize that prenatal PFAA exposure may decrease the concentrations of androgens in mini puberty. OBJECTIVES: To investigate associations between maternal serum PFAA concentrations in early pregnancy and serum concentrations of androgens, their precursors, and gonadotropins during mini puberty in infancy. METHODS: In the prospective Odense Child Cohort, maternal pregnancy serum concentrations of five PFAAs: Perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured at median gestational week 12 (IQR: 10, 15) in 1628 women. Among these, offspring serum concentrations of dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEAS), androstenedione, 17-hydroxyprogesterone (17-OHP), testosterone, luteinizing (LH) and follicle stimulating hormones (FSH) were measured in 373 children (44% girls; 56% boys) at a mean age of 3.9 (±0.9 SD) months. Multivariate linear regression models were performed to estimate associations. RESULTS: A two-fold increase in maternal PFDA concentration was associated with a reduction in DHEA concentration by -19.6% (95% CI: -32.9%, -3.8%) in girls. In girls, also, the androstenedione and DHEAS concentrations were decreased, albeit non-significantly (p < 0.11), with a two-fold increase in maternal PFDA concentration. In boys, no significant association was found between PFAAs and concentrations of androgens, their precursors, and gonadotropins during mini puberty. CONCLUSION: Prenatal PFDA exposure was associated with significantly lower serum DHEA concentrations and possibly also with lower androstenedione and DHEAS concentrations in female infants at mini puberty. The clinical significance of these findings remains to be elucidated.

Toxicokinetics of perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) in male and female Hsd:Sprague dawley SD rats following intravenous or gavage administration.

Poly- and perfluorinated alkyl substances (PFAS) are environmentally persistent chemicals associated with many adverse health outcomes. The National Toxicology Program evaluated the toxicokinetics (TK) of several PFAS to provide context for toxicologic findings.Plasma TK parameters and tissue (liver, kidney, brain) concentrations are reported for perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA) or perfluorodecanoic acid (PFDA) after single-dose administration in male and female Hsd:Sprague-Dawley® (SD) rats.Generally, longer Tmax and elimination half-lives, and slower clearance f, were correlated with longer chain length. Male rats administered PFOA had a prolonged half-life compared to females (215 h vs. 2.75), while females had faster clearance and smaller plasma area under the curve (AUC). Females administered PFHxA had a shorter half-life (2 h vs. 9) than males and faster clearance with a smaller plasma AUC, although this was less pronounced than PFOA. There was no sex difference in PFDA half-life. Female rats administered PFDA had a higher plasma AUC/dose than males, and a slower clearance. PFDA had the highest levels in the liver of the PFAS evaluated.Profiling the toxicokinetics of these PFAS allows for comparison among subclasses, and more direct translation of rodent toxicity to human populations.

Perfluorodecanoic acid-induced oxidative stress and DNA damage investigated at the cellular and molecular levels.

Perfluorodecanoic acid (PFDA) has been widely used in production of many daily necessities because of its special nature. Althoughtoxic effects of PFDA to organisms have been reported, there is little research on the genotoxicity induced by oxidative stress of PFDA on the cellular and molecular levels simultaneously. Thus, we investigated the DNA oxidative damage caused by PFDA in mouse hepatocytes. On the cellular level, an increase in ROS content indicated that PFDA caused oxidative stress in mouse hepatocytes. In addition, after PFDA exposure, the comet assay confirmed DNA strand breaks and an increased 8-OHdG content demonstrated DNA oxidative damage. On the molecular level, the microenvironment of aromatic amino acids, skeleton and secondary structure of catalase (CAT) were varied after PFDA exposure and the enzyme activity was reduced because PFDA bound near the heme groups of CAT. Moreover, PFDA was shown to interact with DNA molecule by groove binding. This study suggests that PFDA can cause genotoxicity by inducing oxidative stress both on the cellular and molecular levels.

Effect of perfluorodecanoic acid on pig oocyte viability, intracellular calcium levels and gap junction intercellular communication during oocyte maturation in vitro.

Perfluorodecanoic acid (PFDA) is a synthetic perfluorinated compound, which has been reported to exert adverse effects on somatic cells. However, its effects on germ cells have not been studied to date. The aim of the present study was to analyze the effects of PFDA on the viability, intracellular calcium levels and gap junction intercellular communication (GJIC) during porcine oocyte maturation in vitro. PFDA negatively impacted oocyte viability (medium lethal concentration, LC50 = 7.8 µM) and maturation (medium inhibition of maturation, IM50 = 3.8 µM). Oocytes exposed to 3.8 µM PFDA showed higher levels of intracellular calcium relative to control oocytes. In addition, GJIC among the cumulus cells and the oocyte was disrupted. The effects of PFDA on oocyte calcium homeostasis and intercellular communication seem to be responsible for the inhibition of oocyte maturation and oocyte death. In addition, since the deleterious effects of PFDA on oocyte viability, maturation and GJIC are significantly stronger than the previously reported effects of another widely used perfluorinated compound (Perfluorooctane sulfonate) in the same model, the use of PFDA in consumer products is questioned.

Evironmental pollutant perfluorodecanoic acid upregulates cIAP2 to suppress gastric cell senescence.

The role of perfluorodecanoic acid (PFDA) in gastric carcinogenesis and its mechanism remains unknown. Our previous research revealed that PFDA regulated the growth of human gastric cells. However, its core molecules and basic mechanisms are still not clear. In the present study, cDNA microarrays were used to determine mRNA changes in AGS cells after treatment with PFDA. DAVID analysis of the genes with >2­fold increased expression in microarray data revealed five genes which were involved in cancer pathways. The most upregulated gene was cIAP2, whose upregulation in AGS was confirmed by western blot analysis and quantitative PCR (qPCR) analyses. In order to investigate the role of cIAP2 in cell proliferation, cIAP2 siRNA was employed to regulate cIAP2 expression following PFDA treatment. The results revealed that the growth rate of cIAP2­knockdown cells was reduced by about 50% compared to the control. Given that our previous flow cytometric assays revealed no significant change (3.7 vs. 6.4%) in the percentage of apoptotic cells when PFDA was added to the medium and cIAP2 expression was upregulated, we next applied flow cytometry to assess whether cIAP2 would lead to cell cycle variations. The research data revealed that the proportion of cells in the G1, S and G2 phases was not significantly altered with the decrease of cIAP2 expression. Finally, the role of cIAP2 in AGS cell senescence was investigated, and the results indicated that cell senescence was significantly increased in the cIAP2 siRNA group in comparison to the control siRNA group. Since p53 has been identified as a tumor suppressor and its molecular alterations are common in different human tumors, we investigated the relationship of p53 with cIAP2. The experimental results demonstrated that cIAP2 regulated the expression of p53 and thus was likely to be a potential mechanism for PFDA­induced growth promotion. Overall, the results revealed that PFDA may suppress cellular senescence induced by p53 through the regulation of cIAP2 protein expression.

Exploring sex differences in human health risk assessment for PFNA and PFDA using a PBPK model.

Perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA), which are classified as perfluoroalkyl and polyfluoroalkyl substances (PFASs), have been widely used in industrial applications as a surface protectant. PFASs have been detected in wildlife and in humans around the globe. The purposes of this study are to develop and validate a physiologically based pharmacokinetic (PBPK) model for detecting PFNA and PFDA in male and female rats, and to apply the model to a human health risk assessment regarding the sex difference. A PBPK model of PFNA and PFDA was established based on an in vivo study in male and female rats. Analytes in biological samples (plasma, nine tissues, urine, and feces) were determined by ultra-liquid chromatography coupled tandem mass spectrometry (UPLC-MS/MS) method. PFNA and PFDA showed a gender differences in the elimination half-life and volume of distribution. The tissue-plasma partition coefficients were the highest in the liver in both male and female rats. The predicted rat plasma and urine concentrations simulated and fitted were in good agreement with the observed values. The PBPK models of PFNA and PFDA in male and female rats were then extrapolated to a human PBPK model based on human physiological parameters. The external doses were calculated at 3.35 ng/kg/day (male) and 17.0 ng/kg/day (female) for PFNA and 0.530 ng/kg/day (male) and 0.661 ng/kg/day (female) for PFDA. Human risk assessment was estimated using Korean biomonitoring values considering the gender differences. This study provides valuable insight into human health risk assessment regarding PFNA and PFDA exposure.

Perfluoroalkyl acid exposure induces protective mitochondrial and endoplasmic reticulum autophagy in lung cells.

Wide application of perfluoroalkyl acids (PFAAs) has raised great concerns on their side-effects on human health. PFAAs have been shown to accumulate mainly in the liver and cause hepatotoxicity. However, PFAAs can also deposit in lung tissues through air-borne particles and cause serious pulmonary toxicity. But the underlying mechanisms are still largely unknown. Autophagy is a type of programmed cell death parallel to necrosis and apoptosis, and may be involved in the lung toxicity of PFAAs. In this study, lung cancer cells, A549, were employed as the model to investigate the effects of three PFAAs with different carbon chain lengths on cell autophagy. Through Western blot analysis on LC3-I/II ratio of cells exposed to non-cytotoxic concentration (200 µM) and cytotoxic concentration (350 µM), we found concentration-dependent increase of autophagosomes in cells, which was further confirmed by TEM examination on ultra-thin section of cells and fluorescence imaging on autophagosomes in live cells. The abundance of p62 increased with the PFAAs concentration indicating the blockage of autophagy flux. Furthermore, we identified the mitochondrial autophagy (mitophagy) and endoplasmic reticulum autophagy (ER-phagy) morphologically as the major types of autophagy, suggesting the disruption on mitochondria and ERs. These organelle damages were confirmed by the overgeneration of ROS, hyperpolarization of mitochondrial membrane potential, as well as the up-regulation of ER-stress-related proteins, ATF4 and p-IRE1. Further analysis on the signaling pathways showed that PFAAs activated the MAPK pathways and inhibited the PI3K/Akt pathway, with potencies following the order of PFDA > PFNA > PFOA. Anti-oxidant (NAC) treatment did not rescue cells from death, indicating that oxidative stress is not the reason of cytotoxicity. Inhibition of autophagy by Atg5 siRNA and chloroquine even increased the toxicity of PFAAs, suggesting that PFAAs-autophagy was induced as the secondary effects of organelle damages and played a protective role during cell death.