Chronic perfluorooctanesulfonic acid exposure disrupts lipid metabolism in zebrafish

Perfluorooctanesulfonic acid (PFOS), a ubiquitous contaminant, has been used in various industrial applications. Currently few studies have documented the effects of chronic PFOS exposure on lipid metabolism, especially in aquatic organisms. The present study defined the effects of chronic exposure to low level of PFOS on lipid metabolism in F0 adult zebrafish and F1 offspring. Our findings revealed a severe fatty degeneration in the liver of F0 males treated with 0.5 μM PFOS and significant ultrastructure changes associated with substance transport or metabolism in liver and intestines (abnormal mitochondria and endoplasmic reticulum, disordered arrangement of inner microvilli within intracellular canaliculus). To address the potential trans-generational effects of PFOS exposure, the early gene expression related to lipid metabolism was measured by real-time quantitative polymerase chain reaction in F1 derived from chronically exposed parental fish. The results indicated that lepa (leptin α), kiss1 (kisspeptins), xdh (xanthine dehydrogenases), and insr (insulin receptor) were significantly upregulated in F1 while dgat1b (diacylglycerol O-acyltransferase), hb9 (motor neuron/pancreas homeobox), and Apoa1 (apolipoprotein A-I) were downregulated. These findings provided evidence that PFOS chronic exposure adversely impacts lipid metabolism in both F0 and F1 and demonstrated the validity of using zebrafish as an alternative model for PFOS chronic toxicity screening.

[Study on the reliability of CardioChek PA for measuring lipid profile]

OBJECTIVE

To evaluate the clinical correlation between the CardioChek PA analyzer (CCPA) and a clinical laboratory reference method to use for screening program purposes.

METHODS

Fasting blood samples were collected on 325 patients (age: 23-86 years). One venous sample was collected using a serum tube for the evaluation on a Beckman reference analyzer. A second venous sample was collected in a lithium heparin tube and was evaluated on the CCPA analyzer. Linear regression analyses and Bland-Altman method were performed for each measured analyte: total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C), triglycerides (TG) and low density lipoprotein-cholesterol (LDL-C).

RESULTS

Our results demonstrated a good clinical agreement for TC, HDL-C, TG and LDL-C(97.0%, 92.9%, 92.4% and 83.7%)in comparison with the CCPA to the reference analyzer. The correlation coefficients were 0.875, 0.813, 0.910, 0.864, respectively. P values all < 0.001. There was no significant difference in the detection rate of hyperlipidemia in TC, HDL-C and LDL-C.

CONCLUSION

We have identified the pre-analytic phase as an important step to guarantee the quality of results and indicated that the CCPA is a reliable lipid point-of-care testing system that can be used for the application of clinical screening anywhere.

Guttiferone K impedes cell cycle re-entry of quiescent prostate cancer cells via stabilization of FBXW7 and subsequent c-MYC degradation

Cell cycle re-entry by quiescent cancer cells is an important mechanism for cancer progression. While high levels of c-MYC expression are sufficient for cell cycle re-entry, the modality to block c-MYC expression, and subsequent cell cycle re-entry, is limited. Using reversible quiescence rendered by serum withdrawal or contact inhibition in PTEN(null)/p53(WT) (LNCaP) or PTEN(null)/p53(mut) (PC-3) prostate cancer cells, we have identified a compound that is able to impede cell cycle re-entry through c-MYC. Guttiferone K (GUTK) blocked resumption of DNA synthesis and preserved the cell cycle phase characteristics of quiescent cells after release from the quiescence. In vehicle-treated cells, there was a rapid increase in c-MYC protein levels upon release from the quiescence. However, this increase was inhibited in the presence of GUTK with an associated acceleration in c-MYC protein degradation. The inhibitory effect of GUTK on cell cycle re-entry was significantly reduced in cells overexpressing c-MYC. The protein level of FBXW7, a subunit of E3 ubiquitin ligase responsible for degradation of c-MYC, was reduced upon the release from the quiescence. In contrast, GUTK stabilized FBXW7 protein levels during release from the quiescence. The critical role of FBXW7 was confirmed using siRNA knockdown, which impaired the inhibitory effect of GUTK on c-MYC protein levels and cell cycle re-entry. Administration of GUTK, either in vitro prior to transplantation or in vivo, suppressed the growth of quiescent prostate cancer cell xenografts. Furthermore, elevation of FBXW7 protein levels and reduction of c-MYC protein levels were found in the xenografts of GUTK-treated compared with vehicle-treated mice. Hence, we have identified a compound that is capable of impeding cell cycle re-entry by quiescent PTEN(null)/p53(WT) and PTEN(null)/p53(mut) prostate cancer cells likely by promoting c-MYC protein degradation through stabilization of FBXW7. Its usage as a clinical modality to prevent prostate cancer progression should be further evaluated.

Abstract P6-04-03: Transcriptome profiling reveals enrichment of luminal feature in aged basal cell population in murine mammary gland

Aging is the number one risk factor for breast cancer development. Increasing evidence suggests the potential of mammary stem cells (MaSCs) and their progenitors to generate certain types of breast cancers through neoplastic transformation. Our previous study has shown increased percentage of MaSC-enriched basal cell population (Lin-CD49fhighCD24med) and increased MaSC frequency during aging in murine models. On the other hand, a recent study from another group showed an increased frequency of CD49fhigh cells in the human luminal population (CD227+) during aging, indicating possible aberrant expression of CD49f in the aged luminal cells. However, how these age-related luminal cells with basal markers are generated and how they contribute to potential breast cancer development remains unknown. Here we apply bioinformatics analysis on Next Generation Whole Transcriptome Sequencing data of MaSC-enriched basal cell population (Lin-CD49fhighCD24med) and luminal progenitor-enriched cell population (Lin-CD49flowCD24high) of both young (4 to 6 months) and old (26 to 31 months) mouse mammary gland to test the hypothesis that age-associated increase of basal cell population and MaSCs may be due to the gain of basal cell markers and features by luminal cells. By Gene Set Enrichment Analysis (GSEA) we found a significant loss of basal cell and basal mammosphere signatures and a significant enrichment of luminal cell and luminal mammosphere signature in the old basal cell population and mammospheres in comparison with the young basal cell population and mammospheres. The core enrichment luminal genes from GSEA are able to cluster the old MaSC-enriched basal cell population as well as mammospheres closer to the cluster of luminal population than to the young basal population. These analyses indicate that aging may be associated with an expansion of aberrant MaSCs with both basal and luminal markers in mice, which may be the precursors of certain types of breast cancer. We are now studying the potential function of the basal-like luminal cells in the aged basal population.

Citation Format: Gu X, Gao H, Wu A, Bandyopadhyay A, Dong Q, Sun L-Z. Transcriptome profiling reveals enrichment of luminal feature in aged basal cell population in murine mammary gland. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-04-03.

MiR-125a promotes paclitaxel sensitivity in cervical cancer through altering STAT3 expression

Cervical cancer (CC) is one of the most common malignancies in women. Paclitaxel is the front-line chemotherapeutic agent for treating CC. However, its therapeutic efficacy is limited because of chemoresistance, the mechanism of which remains poorly understood. Here, we used microRNA (miRNA) arrays to compare miRNA expression levels in the CC cell lines, HeLa and CaSki, with their paclitaxel resistance counterparts, HeLa/PR and CaSki/PR. We demonstrate that miR-125a was one of most significantly downregulated miRNAs in paclitaxel-resistant cells, which also acquired cisplatin resistance. And that the upregulation of miR-125a sensitized HeLa/PR and CaSki/PR cells to paclitaxel both in vitro and in vivo and to cisplatin in vitro. Moreover, we determined that miR-125a increased paclitaxel and cisplatin sensitivity by downregulating STAT3. MiR-125a enhanced paclitaxel and cisplatin sensitivity by promoting chemotherapy-induced apoptosis. Clinically, miR-125a expression was associated with an increased responsiveness to paclitaxel combined with cisplatin and a more favorable outcome. These data indicate that miR-125a may be a useful method to enable treatment of chemoresistant CC and may also provide a biomarker for predicting paclitaxel and cisplatin responsiveness in CC.

Abstract P1-06-04: Bisphenol A treatment induces hyperplasia in primary and stem cell-generated mammary glands from pregnant mice

Breast cancer is a commonly diagnosed cancer of pregnancy. However, how endogenous and exogenous endocrine factors may contribute to the development of pregnancy-associated mammary tumorigenesis is not clear. There is growing evidence that mammary stem cells (MaSCs) may initiate neoplastic transformation when dysregulated in mouse models. We investigated the effect of the environmental endocrine disruptor bisphenol A (BPA) on mouse mammary gland morphology, epithelial cell composition, pre-neoplastic lesions, and the regenerative function of MaSCs. Pregnant FVB mice with GFP transgene on Day E8.5 were implanted with osmotic pumps that constantly release BPA at 0, 25 or 250 ng/kg/day for 28 days and the mice were euthanized one month after weaning. In agreement with the literature, we observed an abnormality of the morphology of the mammary gland after BPA treatment characterized by higher duct density and abnormal secondary and tertiary branching. Quantification of percent hyperplastic mammary ducts in H&E-stained tissue slides revealed a significant increase of ducts with hyperplastic lesions after BPA treatment, particularly with the low dose. To investigate the effects of BPA treatment on MaSCs, we used enzyme digestion to isolate the CD24hi/CD49f+ luminal epithelial cells (also termed as colony forming cell or CFC) and the CD24+/CD49fhi basal epithelial cells (also termed as mammary repopulating unit or MRU) from mammary gland tissues by FACS and found no significant difference in percent of luminal or basal cell population after BPA treatment. Because the basal cells are enriched with MaSCs that can form mammospheres in suspension culture and subsequently form solid 3D organoids when cultured in Matrigel, we transplanted the solid 3D organoids into cleared mammary fat pads of syngeneic FVB mice and immune-compromised nude mice to examine how BPA treatment might alter MaSC function. Significantly, similar to the results from the primary mammary glands, the regenerated mammary glands by MaSCs from mice treated with the low dose of BPA showed increased duct density, secondary and tertiary branching, and a significantly greater number of hyperplastic lesions. Taken together, our study demonstrated that BPA exposure at very low dose could induce pre-neoplastic lesions in the mammary gland of pregnant mice, apparently by directly targeting MaSCs and implicates BPA as an exogenous endocrine factor that may promote pregnancy-associated mammary tumorigenesis.

Citation Format: Bouamar H, Zhang F, Gu X, Dong Q, Sun L-Z. Bisphenol A treatment induces hyperplasia in primary and stem cell-generated mammary glands from pregnant mice. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-06-04.

Effect of transcription factor ZBTB20 on mouse pituitary development

Pituitary, a critical component in the neuroendocrine system, plays an indispensable role in the regulation of body growth. The transcriptional factor ZBTB20 is widely expressed in brain tissues and participates in hippocampal development; however, the detailed molecular mechanism remains unknown. Therefore, the aim of this study was to investigate the effect of ZBTB20 on mouse pituitary development and related mechanisms in ZBTB20 gene knockout mice. The expressional profiles of ZBTB20 in various neuroendocrinal cells during the different developmental stages (from E10 to P0) were described by immunofluorescence staining. A ZBTB20 gene knockout mouse model was then generated. Real-time polymerase chain reaction and western blotting assays were used to detect the levels of five hormones: growth hormone (GH), prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and thyroid-stimulating hormone (TSH). ZBTB20 protein expression was identified from E14 until birth. A majority of the pituitary endocrinal cells were ZBTB20-positive. In ZBTB20 knockout mice, the level of GH decreased by half and PRL expression was eliminated. No significant change was observed in the other three hormones (LH, FSH, and TSH). ZBTB20, an important transcriptional factor in pituitary development, is mainly responsible for the terminal differentiation of prolactin-secreting cells, thereby regulating the secretion of the pituitary hormones.

Establishment of a neuroblastoma mouse model by subcutaneous xenograft transplantation and its use to study metastatic neuroblastoma

The aim of this study was to establish a metastatic human neuroblastoma (NB) mouse model by xenograft in order to study the metastatic mechanisms of NB. A human NB cell line was obtained from a 5-year-old patient and cultured in vitro. A suspension of these cells was subcutaneously inoculated into nude mice at the right flank next to the forelimb. The biological characteristics of the developed subcutaneous and metastatic tumors were analyzed by hematoxylin and eosin staining. The expression of the tumor marker neuron-specific enolase was determined by immunohistochemistry, and the invasive ability of metastatic tumors was examined by a Matrigel invasion assay. DNA microarray analyses were performed to examine the metastasis-related gene expression. Our results showed that tumors grew in 75% of the mice injected with NB cells and the rate of metastasis was 21%. The xenograft tumors retained the morphological and biological characteristics of the NB specimen from the pediatric patient. Neuron-specific enolase was highly expressed in both subcutaneous and metastatic tumors. The metastatic tumor cells possessed a higher invasive capability than the primary NB cells. The expression of 25 metastasis-related genes was found to be significantly altered in metastatic tumors compared to primary tumors, including RECK, MMP2, VEGF, MMP3, and CXCL12. In conclusion, we successfully established a human NB xenograft model with high tumor-bearing and metastatic rates in nude mice, providing an ideal animal model for the in vivo study of NB.

Relation of resistin to proprotein convertase subtilisin-kexin type 9 levels in coronary artery disease patients with different nutritional status

OBJECTIVE

To investigate the association of resistin with proprotein convertase subtilisin-kexin type 9 (PCSK9) levels, another novel regulator of atherosclerosis, in the condition of coronary artery disease (CAD).

RESEARCH DESIGN AND METHODS

We prospectively enrolled a total of 356 consecutive stable CAD patients who were not treated with lipid-lowering drugs in the present study. The baseline clinical characteristics were collected. Plasma PCSK9 and resistin levels were determined by ELISA. The relationship between plasma PCSK9 and resistin levels was investigated.

RESULTS

Overall, plasma resistin exhibited a positive nonparametric correlation with PCSK9 levels (r = 0.123, p = 0.02). When the patients were classified into groups based on body mass index (BMI), the resistin correlated significantly to the PCSK9 levels in patients with BMI < 25 kg/m(2) (r = 0.162, p = 0.026) but not in patients with BMI ≥ 25 kg/m(2) (r = 0.087, p = 0.205). Multivariate regression analysis corroborated the relation between the PCSK9 and an elevated resistin level in patients with BMI < 25 kg/m(2) independently of traditional parameters including age, sex, BMI, smoking, family history of CAD, systolic blood pressure, glucose, low density lipoprotein cholesterol, white blood cell, neutrophil to lymphocyte ratio, and high-sensitive C-reactive protein.

CONCLUSIONS

Plasma resistin was positively related to PCSK9 levels in CAD patients with normal weight, suggesting that the circulating resistin might represent a link with PCSK9 level variations in CAD progression of normal body weight.

Elevated TrkA receptor expression is associated with all-trans retinoic acid-induced neuroblastoma differentiation

Neuroblastoma is the most common and one of the deadliest among pediatric tumors; however, a subset of infants with neuroblastoma display spontaneous regression. The mechanism of spontaneous regression remains to be elucidated. TrkA plays an essential role in the differentiation and functionality of neurons; abundant TrkA expression is associated with favorable prognosis of neuroblastoma. All-trans retinoic acid (ATRA), a first-line drug for acute promyelocytic leukemia (APL) treatment, has been shown to induce differentiation and inhibit cell growth. Neuroblastoma tissues in our hospital inpatient were collected, primary cell culture was performed, and the cells were separated and purified to be cell line. Trypan blue exclusion was used to count the numbers of cells alive, morphological changes were observed under the phase-contrast microscope. RT-PCR was used to determine the expression level of TrkA. In this study, a human neuroblastoma cell line was successfully established; in addition, we demonstrated that ATRA induces growth arrest and promotes the differentiation of neuroblastoma cells. In addition, ATRA was shown to significantly increase the levels of TrkA mRNA expression. Therefore, we concluded that the elevated expression of the TrkA receptor is associated with ATRA-induced growth arrest and differentiation o neuroblastoma cells. The results of this study provide a theoretical basis for the clinical application of differentiation-inducing ATRA for neuroblastoma therapy.

Long-term efficacy of sitagliptin as either monotherapy or add-on therapy to metformin: improvement in glycemic control over 2 years in patients with type 2 diabetes

OBJECTIVE

To evaluate the efficacy of once daily sitagliptin 100 mg as monotherapy or as add-on to metformin in patients with type 2 diabetes mellitus (T2DM) over 2 years of treatment.

RESEARCH DESIGN AND METHODS

The monotherapy analysis used pooled 104 week data from 64 patients in two randomized, double-blind trials evaluating the safety and efficacy of sitagliptin monotherapy. Data used were from patients who were randomized to sitagliptin 100 mg/day, were not on an antihyperglycemic agent at the screening visit, had baseline A1C of 7.0%-10.0%, and had Week 104 A1C measurements. The add-on to metformin analysis used pooled data from 347 patients in two randomized double-blind trials evaluating the safety and efficacy of sitagliptin + metformin combination therapy. Data used were from patients who were randomized to sitagliptin 100 mg/day + metformin ≥1500 mg/day, had baseline A1C of 7%-10%, and had Week 104 A1C measurements. Excluded from either analysis were patients who discontinued prior to 2 years (e.g., due to lack of efficacy, a need for rescue medications, or adverse experiences). Analysis endpoints were A1C, fasting plasma glucose (FPG), HOMA-β, proinsulin/insulin (P/I) ratio, and for monotherapy, 2 hour post-meal plasma glucose (PMG).

RESULTS

For the pooled monotherapy cohort, after 2 years of treatment, mean A1C, FPG, and 2 hour PMG decreased from baseline values of 7.9%, 156 mg/dL, and 223 mg/dL to 6.9%, 143 mg/dL, and 191 mg/dL, respectively, while HOMA-β increased from 67% to 85% and P/I ratio improved from 0.57 to 0.28. For the pooled add-on to metformin cohort, after 2 years of treatment, mean A1C and FPG decreased from baseline values of 7.7% and 160 mg/dL to 6.9% and 140 mg/dL, respectively, while HOMA-β increased from 50% to 62% and P/I ratio improved from 0.33 to 0.28. These analyses are limited in that only patients who were able to complete 104 weeks of study were included.

CONCLUSION

In the subset of patients with T2DM who maintained and completed treatment for 2 years with sitagliptin as monotherapy or as add-on to metformin, improvements in glycemic control and measures of β-cell function were observed over the course of treatment.

Reverse-dipper pattern of blood pressure may predict lacunar infarction in patients with essential hypertension

BACKGROUND AND PURPOSE

The fluctuation of circadian blood pressure (BP) is of great diversity in patients with essential hypertension and may provide significant prognostic value for stroke. However, it remains uncertain whether reverse-dipper pattern of BP influences the incidence of lacunar infarction in hypertensive patients.

METHODS

In the current study, 362 hypertensive patients (195 males, 167 females) were enrolled. BP patterns were evaluated with 24-h ambulatory BP monitoring (ABPM). Multinomial logistic regression was applied to analyse the possible relationships between lacunar infarction and various clinical risk factors such as ABPM.

RESULTS

A total of 93 patients (25.7%) had reverse-dipper BP pattern. Non-dipper pattern of BP was observed in 179 hypertensive patients (49.4%) and dipper pattern in 90 patients (24.9%). The percentage of lacunar infarction was the highest in the patients with reverse-dipper pattern compared with pure hypertension or atherothrombotic cerebral infarction (P < 0.05). After multinomial logistic regression analysis, reverse-dipper pattern of BP (odds ratio 2.492; 95% confidence interval 1.133-5.479; P < 0.05) and age (odds ratio 1.084; 95% confidence interval 1.047-1.123; P < 0.01) were found to be directly associated with lacunar infarction.

CONCLUSIONS

Reverse-dipper BP pattern may serve as an independent risk factor for lacunar infarction and more personalized BP management should be offered to the patients who have elevated nocturnal BP.

Bosentan protects the spinal cord from ischemia reperfusion injury in rats through vascular endothelial growth factor receptors

STUDY DESIGN

Experimental study.

OBJECTIVES

To investigate whether Bosentan, an endothelin-A/-B dual receptor antagonist, could protect neurons after spinal cord ischemia reperfusion (SCIR) injury in rats and its underlying signaling pathway.

SETTING

Department of Neurosurgery, the Second Affiliated Hospital, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi Province, China.

METHODS

Sprague-Dawley rats were randomly divided into two groups, saline group (IRS, n=48) and Bosentan group (IRB, 5 mg kg(-1), n=48). After ischemia for 1 h with occlusion of the infrarenal aorta, spinal cord were reperfused for 6h, 12h, 24h, 3d, 5d, and 7d separately. Enzyme-linked immunosorbent assay was used to detect vascular endothelial growth factor (VEGF) in serum. Immunohistochemistry was performed to detect protein expression of VEGF, VEGF receptor 1 (FLT-1) and VEGF receptor 2 (FLK-1). Gene expressions of VEGF and its receptors were evaluated using the quantitative reverse transcription polymerase chain reaction.

RESULTS

Compared with the IRS group, gene and protein expressions of VEGF, FLT-1 and FLK-1 were significantly increased (P<0.05), so was the concentration of VEGF in plasma (P<0.05). FLK-1 was expressed on spinal cord neurons.